You’ve Got to be Nuts to Eat a Cashew Nut Shell

Last November we joined our next door neighbors on a lovely trip to Brazil.  We saw lots of interesting places, met lots of interesting people, ate lots of interesting foods.  One food in particular fascinated me, the cashew.  For most Americans the cashew is just a nut (like a walnut or almond) and we don’t think too much about where they come from or what they look like.  My grandparents used to always have a bowl of shelled nuts and a nutcracker that you had to use to break the shells, so I had a pretty good idea of what a walnut and almond looked like in their natural habitat.  Not so with cashews.  In Brazil cashews are primarily a fruit (usually consumed as a juice) and only sold as an afterthought to tourists on the beach as the roasted nut that we know in the States.

The fruits themselves are very unusual, so it was great to see them in the local market and understand how they grow.  First the nut part appears on the tree (see the cashew nut shaped object on each fruit below), then the fruit grows after it.  Very different than your regular apple, pear, or peach.

Fresh Cashews at the Market
Fresh Cashews at the Market

Our host family usually had cashew juice for breakfast every day which I enjoyed.  The flavor is a little difficult to describe, but think of combining a lime and orange and a mango together and you are getting close.  They even brought a cashew home from the market so I could try the fruit directly.  We brought it back to our apartment and it sat in the refrigerator for several days.

On the day before we were to leave Brazil, I decided to try and eat the fruit.  It tasted pretty much like the juice, with a slightly mushy pulp.  The juice of the cashew squeezes out of the pulp so you are just left with a flavorless glob of pulp that you spit out.  Not too bad.  Now I had this nice little cashew nut shaped shell in my hand, I wondered if there might be a nut inside.  There is only one way to find out.  First I tried using a knife from the kitchen, but as I worked at the leathery slippery skin I was worried that the knife would slip and I might cut myself.  So why not just bite it open?  Okay.

I stuck the nut in the corner of my mouth to get a good grip on it and bit down.  Hmmmm, that tastes very odd.  Wow that tastes really bad!  A bitter taste spreads through the side of my mouth.  My teeth and inside of my cheek become sticky.  The corner of my lips start burning.  I ran to get some water to try and stop the burning and it didn’t work.  Next stop, the Internet!

Thanks to Wikipedia I found out:

The seed is surrounded by a double shell containing an allergenic phenolic resin, anacardic acid, a potent skin irritant chemically related to the more well known allergenic oil urushiol which is also a toxin found in the related poison ivy. Some people are allergic to cashew nuts, but cashews are a less frequent allergen than nuts or peanuts.

GREAT!  So basically I’ve just been chewing on the equivalent of poison ivy or poison oak.   Time to break out the big guns and start treating this like a poison ivy infection.  First I brushed my teeth with toothpaste.  Sort of helped.  Next I literally washed my mouth out with soap.  Bar soap didn’t work so well, dishwashing soap was better.  More water and more spitting later seemed to resolve most of the pain.

Then back to the Internet to find out what you are supposed to do if this happens.  Interestingly, they don’t say very much about this.  Do I go to the hospital?  Am I going to have a major allergic reaction on our flight back from Brazil?  We called up our host family and they just laughed and said you aren’t supposed to do that, and started to tell all their friends about what the silly American did with the cashew fruit.

That night the corner of my mouth just stung, but it was bearable, the flight back to the U.S. was okay, but things went downhill from there.  First my belly started itching, then my butt, then my arms, legs and under my neck.  I never really broke out in the usual poison ivy type sores, but everything was itchy.  Seven days after the incident I woke up and couldn’t see out of my right eye.  Nothing itchy, but just all completely puffed up.  This went on for a few more days before things started getting back to normal and most of the itchiness was gone in about a month.

Day 7 After Biting Cashew Nut Shell
Day 7 After Biting Cashew Nut Shell

So it turns out the one reason you never see raw cashew nuts (in or out of the shell) anywhere is that the nuts are surrounded by a nice little poison.  The pickers of cashew fruit are often affected by this oil, but that’s usually about it.  All cashew nuts that are sold are actually roasted to deactivate the toxin in the shells which is why you never see true “raw” cashew nuts for sale.

So next time you are eating unusual fruits that you know the fruit is edible and the nut is edible, stop for a second and check the Internet to see if some other part of the fruit might be poisonous.  You have been warned.

88 thoughts on “You’ve Got to be Nuts to Eat a Cashew Nut Shell”

  1. Thank you so much for posting this information. I just returned back from a trip in Honduras where I too, let my curiostiy get the better of me…..after trying the interesting fruit, I decided I’d try to get to the nut. I bit the shell thinking it would crack easily and reveal to me a delicious cashew. Clearly, I knew NOTHING about cashews and the laborious process of de-shelling them. Initially the bitterness was bad but the burning sensation in my mouth and throat became HORRIBLE. What’s worse, I was part of a walking tour group, no where near bathrooms or water or anything to rinse my burning mouth. That was 7 days ago. The insides of my mouth are still covered in burns and it hurts to eat hot, cold, spicy, foods. I do have a few rash spots from where I wiped the my hands after biting into the death shell. Again, in doing that, I had no idea that the oil from the shell is in the same family as poision ivy/oak, etc. Oh, the trouble my curiousity has caused. So, after seeing the picture of what it did to you, I’m hoping I am not soon to face the same impending doom. Hopefully my misery is limited to a few minor rashes, a burned mouth, and minimally damaged pride!
    Thanks again for sharing!

  2. Gretchen,

    I’m sorry to hear that this happened to you, but glad to know I’m not the only one in the world that would try it. 🙂 The strange thing was that the eye puffiness didn’t happen until much after most of the basic redness went away. My eyes never got itchy and they definitely started looking better after I got out of bed for a while so the fluids could drain out a little more. If you feel up to taking a couple photos I would be happy to post them or link to them on the Cashew Nut Shell Eaters Wall of Pain (to be created if I get some more photos).

    On a side note, do you consider yourself an adventurous eater? I guess I would have to put myself into that category as I did try fugu (potentially poisonous blow fish) while I was traveling in Japan. What other adventure foods have you tried?

  3. i have read about this before its pretty interesting but damn glad ur ok, that must have sucked, just for more info on half poisonous food have you ever heard of rhubarb? well if you ever buy it fresh or see it growing what ever you do, do NOT eat the leaves, surprisingly the stalks/stems are tasty and healthy but the leaves can make you very sick or even kill you.

  4. Yes, having grown up in the northeastern part of the U.S. (and as a huge fan of rhubarb) I did know about the danger of the leaves, probably just as everyone in Brazil (and other countries that have cashews) know never to eat the cashew nut shell.

  5. Guess what….
    I have done same like you…. First i bited it, then i just thought to wash with water, then ate some sugar by thinking it will stop,but no;
    Then i thought it must be some toxic acid and salt is a base….so i took a bit on my finger and rubbed on my tongue……. First it was like to burn but after that it just little cooled down…….
    But again it start to burn…..
    Now i am in a great trouble, what to do?
    Should i consult a doctor ??
    Plz reply soon….

  6. First Sorry 2nd m happy to know that m not the only silly person in the i was wondering in a kind of forest in Nigeria i got happy to find the cashew nuts free of cost and then i tried to break the shell with my teeth..since that time m feeling that my toung is burining,bt i dont know what should i do??

  7. Can I be #4 in the Cashew Nut Shell Eaters Wall of Pain? I bit on one today, naively expecting to find a perfectly roasted cashew nut inside.
    My greatest fear is that the allergic reaction will occlude my respiratory tract. In that case, I just hope the onset will be slow enough to allow me to go to hospital.
    I’ll post my experience in a few days’ time. Fingers crossed!

  8. I have cashew tress that I grow in the Cayman Islands. If you roast the nut indoors, just the fumes will also give you an allergic reaction as its so toxic. I learned that the oil from the shell is used in furniture polish hence what you are tasting could be the equivalent of drinking furniture polish 🙂 The fruit is lovely but the roasting takes place outdoors. Good Luck but please dont give up on eating the fruit and nut the correct way!

  9. Don’t worry, I still love cashews (the nuts) and love cashew juice and fruit as well. I might just think twice next time I start eating a new fruit though…. (or at least check the Internet). How long do the cashew nuts need to be roasted to deactivate the poison? Have you ever tried a “raw” cashew nut or is that impossible given the toxic oil? Is the oil only in the shell or also in the nut itself?

  10. Nutter #4 debriefing. Day 6, nothing happening. The cold sore-like scab on my lips and corner of my mouth have now gone. No itching apart from the usual mosquito/sandfly bites.
    I didn’t go to the doctor, but I saw some random internet advice to take vitamin C to boost the immune system, which I did. I doubt that alone prevented a reaction, which varies from person to person, but there you go.
    In case other people are worried, what you can do is to buy an adrenaline auto-injector (e.g. epipen) to stop a life-threatening reaction.
    Where I live, epipen needs prescription, and I couldn’t be bothered to go to a doctor with no symptoms, just an embarrassing story.

    To answer Matthew’s question, my understanding from the various bits I read around is that the acid oil is only in the shell, not in the nut. Allergy to the edible nut is also possible, but it’s a completely different allergen. The allergic reaction we are discussing here is caused by the skin cells that are slowly mutated by the acid, and are therefore no longer recognised as part of your body by your immune system.

  11. Oooh, apparently I’m nutter #5, not 4. Definitely good to know I’m not the only fool to have done this.

  12. yesterday my mom bought cashew nuts to my curiosity i took the shell then boiled it. then i opened it with my hands to get the nuts then next thing i know my hands became rough then everytime i wet it became rugged and i can see my fingers became white it looked like it was painted with white paint and i am really worried i searched the internet i can’t find any answers i want to know how to treat it hope you can help me and sorry about my english 🙂

  13. Hi,
    I am happy to know that I am not the only person in a world which decided to bite on cashew nutshell!
    Today is the third day since the accident and my lips peeled but I have a burn on my cheek and worried if it will ever go away or I am left with scar for life.
    does anyone know? please answer, I am really worried…

  14. I thought I had seafood poisoning and wrote it off as such until…

    …It all started when a Salvadorean friend of mine and I stopped by Mexican market to get some things for a barbeque. I opened a raw cashew and experienced the same horrors, only to assume that it was seafood. Two weeks later I opened another raw cashew and while looking for directions on how to grow a cashew into a tree, I found this website. To my amazement I had found the cause of my allergic reaction and by the next morning started feeling the results. its been a week since my second exposure, it was not as bad as the first and have been taking kirkland’s (Costco’s brand) form of Zyrtex. It is an Antihistamine. Overall the itching is going away and although the swelling on my eyes have gone down, it has left extra wrinkles from the stretching. I am confident that my lower eyelids will return to normal though. If not, I will post. STAY AWAY FROM RAW-UNPROCESSED CASHEW NUTS!

  15. My bf n I love cashews n started thinking the same thing you did; what do cashew shells look like? You answered our question and more. Great story. Ty 😉

  16. I’ve been asking people why you see other nuts in the shell but never cashews sense about 1971 when I was 15 yrs old. Just kind of a personal research project. Never got a positive response. Finally one day about year 1999 a friend brought me a comic strip page from the Sunday funnies. There in the “Ripley’s, beleave it or not!” section there was the definitive answer. What an amazing find and an amazing place to find it. After 20 Yrs in the US Navy and having visited several South American ports and seeing whole cashew fruits I never tried it because nobody was ever able to answer my question. Lucky me?

  17. I decided I’d try to get to the nut. I bit the shell thinking it would crack easily and reveal to me a delicious cashew. Clearly, I knew NOTHING about cashews and the laborious process of de-shelling them. Initially the bitterness was bad but the burning sensation in my mouth and throat became HORRIBLE. What’s worse, I was part of a walking tour group, no where near bathrooms or water or anything to rinse my burning mouth. That was 7 days ago. The insides of my mouth are still covered in burns and it hurts to eat hot, cold, spicy, foods. I do have a few rash spots from where I wiped the my hands after biting into the death shell. Again, in doing that, I had no idea that the oil from the shell is in the same family as poision ivy/oak, etc. Oh, the trouble my curiousity has caused. So, after seeing the picture of what it did to you, I’m hoping I am not soon to face the same impending doom.
    Thanks again for sharing!

  18. Glad to hear that I’m not the only one with curiosity about cashew nuts. The swollen eyes only happened for a few days and only were really bad right when I woke up in the morning.

  19. Happened to me yesterday. Was hiking on a nearly undeveoped tropical island in Cambodia when I found a few cashew trees with a few fruits on. I kew you could eat the fruit, but I never heared about the CNSL… So I tried to bite the nutshell open with my teeth. I gotbthe nasty stuff even down my throat, and my whole mouth, lips and throat started to burn. I didnt beliefe it could be toxic until I came back after 4 hrs and googled it up. That was a shock. Silly me..
    Its now day 2 and I dont have any sicnificant reaction so far. Lips and mouth still feel weird.
    I was thinking that maybe not everyon gets an allergic reaction cause the stuff is already that long in my body and my skin was contaminated long time ago. But thats hard to believe if you read whats the nutshell oil containing of.
    Now I dont know if I should stay on the island or go back and search for a doctor. A doctor from back home told me the only thing they could do would be tto give me painkillers.

  20. Sorry to hear about your cashew incident. Based on what doctors told me, they really can’t do anything either so you are better enjoying your trip (as best you can).

  21. Another cashew nutter here too. Picked a few windfalls in India about 3 weeks ago. We tried the attached cashew apples there and then, the fragranced taste and texture reminding me slightly of jackfruit in Thailand.
    Decided to crack open one of the drupes (shells) this morning. Bad idea, hands covered in viscous oily substance which washed off with soap and water. The ‘nut’ was too soft anyway, but I tried it nevertheless. Minor stinging to mouth and tongue, eyes a little bit red about an hour later (although I did wonder whether it might be early hayfever as the sun has finally appeared in London today after its abepsence since last October!).
    Stomach feels a bit tight, but think I’ll probably survive (famous last words)…

  22. Thank you for posting everyone, because I now know what I did as well.

    I was in costa rica and the cashew trees were in the backyard of where I was staying. I did not eat the nut shell but I broke it open with my hands to see the nut inside and washed them immediately after. I knew not to bite into it because someone told me they had to be roasted first or it would cause your mouth to burn. However I did not know I could get an allergic reaction just from touching it.

    The next day I developed a rash on my arm. I thought it was heat rash so I stayed inside for 2 days and took cold showers but it kept spreading and my face and eyes kept getting more and more swollen. Each day I woke up the swelling on my eyes looked grotesque other parts like my arm and neck have swelled as well. The rash has spread everywhere. I setup a doctor’s appointment the day I got home.

    My doctor said it looked like poison oak so I googled poison oak and costa rica and cashew tree came up – immediately i was able to pull this post up – see the picture and know what I had done.

    They just gave me a steroid shot and prescribed prednisone – i’m hoping this sloth face goes away soon.

  23. This is crazy!!!! I ate the fruit 2 days ago 19th may 2013 and like many of you, curiosity got the best of me; I bite the shell to get to the nut and was Greeted with a terrible and disgusting taste along with instant burning on my lip I dropped it and ran to the bathroom and brush my teeth and used mouth wash. Today 21st may 2013 I have bruises/burn marks where the liquid touched my lip and I hate to see them, can anyone tell me how long will it take to clear up?????

  24. Yes, stupid us! Just picked one TODAY on our honeymoon and tried to open it with our teeth. After much burning and washing we decided to google it and found this forum. Just burning now, but from what I’ve read the worst is yet to come! Yikes!

  25. Hopefully the best is yet to come in your marriage, but your are right, the burning mouth is just the beginning. But now you can have a story to tell the family over and over again about your cashew nut experience. Hopefully you’ll feel better soon and not have too bad a reaction.

  26. on vacation with my boyfriend in sao paulo. he bought me the forbidden fruit last night in the local supermarket. being a curious cat my self, ofcourse I bit into the nut. it was really burning, washed my lips with face wash. woke up this mornng, i have burns on the sides of my lips, i resemble a joker… I really hope thats where it stops and I wont feel any thing else.

  27. Avi, I’m in Sao Paulo too and just bit into the raw cashew shell! What kills me is that I asked the clerk at the supermarket if I could eat all the whole fruit and whole nut, and he said yes. I guess it didn’t occur to him that I didn’t know you had to cook the nut first. But as soon as I bit into it, it was obvious that this wasn’t such good idea. Anyhow, I just took an antihistamine and a drank a bunch of water and am hoping for the best. Big thanks to you, Matthew, for starting this thread. I feel relieved that I now know generally what to expect.

  28. I had a bite in Mozambique many years ago, the memory is still vivid. I believe I lost all skin inside my mouth, I could peel it out. Horrible pain! No swolling though.

  29. Hmm, about 20 min ago that I lost my biting-into-a-raw-cashew shell virginity, plus the effort trying to get the nut out and all the whitish oil all over my hands. Found this site because the burning sensation in my mouth and throat made me think maybe I shouldn’t have done that. First I was curious, then I was like what the fuck, now I’m kinda scared…sad face

  30. Welcome to the “adventurous eaters club” Morten. Hopefully your symptoms won’t be any worse than mine, but be prepared for a couple of uncomfortable weeks to come. Oatmeal bath is supposed to help, but I never got that bad that I really wanted to try that…. Just wash/brush as much of that oil out as you can.

  31. So I didn’t escape the symptoms. First day my tongue was numb, and then the second day the rash started. First on the oppposite side of my elbow on both arms and a little on the side of my stomach. Now on the fourth day, and the rash has spread a lot. All over belly, arms, armpits, private parts, and starting on my neck, back and chest too. The skin is also peeling off my hands.

    I have one question though. I read the crappy chemistry in the caju is also present in the mango and pistachio. Have any of you silly people who decided to try to eat a raw caju had problems with mangos or pistachio later on?

  32. Wow, sounds like you must have gotten more of the oil than I did or are particular allergic to the chemical.

    No problems with mangoes or pistachios after my particular event, but I’m not particularly allergic to poison ivy and it didn’t sound like I got nearly as much of the chemical in my system after my event.

  33. Hi, I was born in Panama central america we have a lot of cashews trees. Cattle growers use the trees to make live fence poles and in the dry season the cows and horses can get some water from the fruit. As a little boy I was warned not to bite the cashew nut. But the wild parrots love to open the green nuts and eat the inside. We have a beach tree known by the name manzanillo. The fruits is shiny green and then turn to a shiny red. beautiful but is very toxic. Even is you took shelter under the tree you will begin to swell. sometimes the american and european tourist try to bite the fruit and later rush to the hospital.

  34. From what I’ve heard there’s no such thing as completely “raw” cashews. Even according to the web page you provided, the nuts are still processed with heat (40°C) which may complete the job of deactivating the irritating oil. However, I haven’t seen anything that specifically mentions a temperature at which the oils are deactivated.

  35. Hi there, I did the exact same thing in Brazil about 15 years ago. Since then I have become quite intolerant to nuts, I get a red sores on the side of my tongue – I think pistachios, and walnuts and pecans trigger this reaction, funnily enough not sure about cashews, though the others only when eaten in large quantities, I was wondering if anyone else had sustained late onset nut allergies?

  36. A barber in the Philippines got the idea od using the nut shell in his shop to remove mold from their costumers. Later on, got also the idea of putting the product on the market for that purpose and has a thriving business.

  37. Matthew, thanks for this blog. Good to hear that I’m not the only one who puts unknown things into the mouth. My wife is laughing that I behaved like our 15 months baby.
    My story is exactly like others – seen a lot of cashew in supermarkets in Poland. Love to eat it. When visited Goa I have seen on the drawings how the fruit looks like, so I wanted to see the tree. Taxi driver took me to the place and I got my trophy – fresh, original & very interesting fruit.
    Back in the hotel I decided to try it. Did not have any knife so just bite a piece. Good that I was in hotel room, so I could flush my mouth immediately with water. I did not swallow it. At the beginning I thought that it’s just a bitter taste, but started to worry when my lips and tongue become a little white. When goggled it, it was more clear and at least I was relaxed that I’m not going to die  I lost the taste in my mouth for about 6 hours, and actually on the next day I feel not so bad.
    It was 2 days ago – now I have 1 cm round brown spot below my lips corner, and burned lips. Anybody can advise – when such a scar go?
    Hopefully I will not have any rash, but again – thanks to the information here at least I would not be surprised.

  38. I haven’t had the “privilege” of eating a raw cashew from the shell like some here. Lucky for me I guess!

    Cashews used to be prohibitively expensive due to the old method of roasting and extracting the nuts. They were famous for spitting out the urusinol while roasting and getting on people doing the work – I’m sure that was fun. These days the cashews are mostly processed by water, and that allows them to extract the urusinol from the water, crack the shells by water swelling and easily extract the nuts. At this stage these nuts are labeled as “raw” although they have been processed with minimal heat, and they are much sweeter than roasted cashews.

    Also note that mangoes have the same urusinol at lower levels in the skin. It’s what causes the brown and black stains on the skins when they are damaged. I’ve gotten itchy lips from sucking on a mango to get all the juice, and I generally don’t even react to poison ivy anymore.

  39. Add another one! I’m a chef, so I’ll eat anything! Well, lesson learned. An hour later I’m a bit more comforted by this thread. An hour later, the burning has subsided a little, so now I’m waiting for whatever’s next. Ill take some antihistamine and hopefully won’t swell up.

  40. Thank you very much for posting such helpful comments. My coworker brought me some cashews today. Silly, I decided to try the nut and after washing it, I had a bite and swallowed it. Horror!!! I washed my mouth, brushed my teeth, had a fresh squeezed beet/carrot/ginger juice. Nothing helped the burning numbing sensation. Well, I started to google, and I found this site with personal experiences and handy tricks. I washed my mouth again with nontoxic dishwasher liquid with lavender essential oil, brushed my teeth, tongue, gums, soft palate with Sensodyne, used the herbal mouth wash, then applied Calamine lotion on my lips; plus took Zyrtec. I hope that I will skip some of the allergic reaction, because I have my vacations soooon! Definitely, talking to my coworker tomorrow; she just had to mention something to prevent me from this silly and unpleasant experience.

  41. Another dumb tourist here. Had the delicious fruit in Brazil and curiosity got of me. Bit into the husk and immediately was over taken by a burning sensation on lips and tongue. No big deal. Lips turned white and tongue got numb. 2 days later and woke up to swollen lips and my belly button and below my crotch itches like hell haha. Will see if this hotel has anything for it. Time to ride the lightning

  42. I had a similar experience in Peru this summer with a raw cashew in the shell. Dug the seed/nut out w/my fingers and tasted it. Reaction started the next day and got progressively worse so that I eventually looked like that fetching picture of you w/the swollen eye. Couldn’t figure out why the reaction was so bad until I realized that the 15 or so cashew trees surrounding us in the jungle were releasing pollen every day that I was inhaling. I suspect the pollen is toxic, too.

    But, here’s the deal: I’ve been allergic to mangos for years. Mangos are in the same family — anacardiaceae— as cashews, poison oak/ivy, and pistachios. The skin of the mango contains urushiol, the toxic irritant, as do the shell of the pistachio and cashew. I just heard that sixth graders at the school where I used to teach have discovered a new game with pistachio shells: rub the shell on the ground back and forth under your foot (the friction releases the urushiol, I guess, though I hear there’s also some other crazy combustible quality to pistachio shells), and quickly throw it at your victim or place it on their skin. The result: a huge blister, a pistachio burn.
    Oy vey!
    Mangos, pistachios and cashews are three of my favorite foods, but you won’t see me eating any of them any time soon. That nasty skin reaction lasts for weeks!
    Thanks for the post and gruesome picture!

  43. Yes, I bit the cashew nut too. It happened when I was a kid. I grew up in Cuba and there the cashew fruit is a common fruit, but Cubans only eat the “fruit” (or pseudo fruit) and the nut (what they call “seed”) is just thrown away. Being young and curious, I decided to find out what the cashew nut tasted like… then I had one of the most horrible experiences I remember from childhood. Apparently I did not give it a good bite, so my tongue only went burning for some hours. Nor water, nor sugar nor anything I tried would help. As grew up, I went trying wasabi, jalapeño and some other really tough things but nothing comparable to that fresh cashew nut. I thank all the people that have posted their comments here for others to learn. I wonder why so many people (even in Cuba) knows about poison ivy and other toxic plants and they know so little about the danger of biting fresh cashew nut.

  44. Ah, the joys of cross-allergies… I have not experienced the ‘revenge of the cashew’, but I can tell you that if you are allergic to poison oak/ivy/sumac, then there is a good chance you will also react negatively to mangos as well any other plant containing urushiol oils – like the cashew. It is common to become more sensitized and reactive at every exposure. In my case, I’d had a nasty case of poison oak as a child and know to keep my distance, but I had no idea that there were other dangers lurking in the local supermarket.
    My particular romp through urushiol hell took place when I decided to save some money and buy whole mango fruit and chop it myself rather than buying it already prepared. I might have escaped with little more than slightly irritated hands – but for the unfortunate decision I made right after peeling and cutting up a couple of mangos. I’d just finished washing up the kitchen and I remember thinking that I had just enough extra time to break out the trimmer to freshen up my ‘brazilian’ before hopping in the shower and getting ready for work…
    Needless to say, the burning to my tender lady bits was excruciating within a few hours and I was living on benadryl and vicodin for about a week and a half just to keep from going insane from the burning and itching. It was nearly a month before things were back to normal. Since then, even eating fresh mango will set my mouth to tingling.
    Be careful and aware of what you eat and where you go if you’ve had a bad reaction. There are people who have had breathing difficulties and skin reactions just from walking near mango trees – I imagine the same would be true for cashew trees or any of the poison ivy/oak/sumac family.

  45. Thank you for this thread. I’m out in Cambodia visiting and ate the nut also. I should know better than to do such a thing *slaps hand on forehead* it happened four days ago. Beginning Sx were the same (burning and stinging after eating) Rash Around my mouth started the next day and has progressively gotten worse and some has spread on my hands and arms as well. I am using hydrocortisone cream and taking antihistamine. Yesterday woke up with puffy redness in left eye, but it subsided by the afternoon. On day four, so hopefully the Sx are peaking. Thanks again for this post and everyone’s feedback. I’ve been the talk of the trip and I think we should put out a t-shirt that says “I ate a raw cashew nut and survived” (;

  46. I’ve joined this club of people that try strange things … I bit the cashew nut skin an immediately felt a burning sensation in my mouth and on my tongue. Not cool… after an hour my eye started to swell and burn also… a shot of pred and piritan later.. and meds for the week.. hoping its not as bad as some of you guys… note to self… don’t ever eat cashew nuts raw again

  47. I too became a victim of biting a cashew shell. ..But,I just had burning sensation in my tongue till now… As soon as ,it tasted bitter ,I threw the shell off. Hope,nothing worse occur after this…

  48. I also bit the shell, in the lush gardens of a respected townsman in Nigeria. The liquid within burnt like acid; the skin of my lips and inside my cheek. It took a day to really hurt, which helped as we were about to sit down to lunch and refusal would have greatly offended. It was less greedy guts and more curiousity though as to why I was “spoiling me dinner” 🙂

  49. I see this thread is still going- there is very little info about this on the internet. I just ate some cashews from Costco and oh the yuckiness. It brought be right back to an experience I had over 15 years ago in Ghana. Just like you all described, except my symptoms only lasted a day. This time I have the luxury of the internet, so I thought I’d get to the bottom of things. I think I’ll take these back to the store!

  50. It happened to me while I was working as a volunteer in Mozambique a few years ago. I was eager to find out what a fresh cashew nut would taste like, expecting a taste sensation similar to almond or pecan nut fresh from a tree. What a cruel awakening! My lips burned, then went numb, eventually a crust formed and then peeled off. After a week everything was more or less back to normal. I had no itching or swelling. I tell everyone about my experience to warn them, and a friend who heard my story has come across this site and sent the link to me. Thanks to everyone for sharing their stories!

  51. Well, I got from my son spice from India in a little plastic bag. There was cardamon, chilli, pepper….and a shell in the form of a Kidney. I thought the spices where made for a stew. So everything in a chicken soup. After the cooking I took out the little kidney. Opened the shell and ate the cooked seed. It felt fat in my mouth and sicky like glue. I asked on Facebook, if somebody knew that kind of spice ;). Somebody told me it was a cashew nut and you may not eat the shell because it gives irritation. So now I don’t know what will be the effect in my body. I made a poison chicken soup!!

  52. I did the same in about 2002, while backpacking in Guatemala. Someone gave me a cashew fruit, and it was delicious! I tried to eat the seed as well. I took one bite, and my mouth, lips and tongue stared tingling and then got numb. I didn’t have any soap, but rinsed my mouth out with water. My mouth stayed numb for the rest of the day. A few days later, I broke out in angry, horribly itchy hives all over my body that stayed for eight days.

  53. I did the same thing in Brazil back in November ’15. We had cashew fruits and I tried to bite through the shell to get the nut. At first it started tingling in my lip, but I just thought it was spicy/hot so I kept trying to chew through the shell. As the tingling became worse and there was a really sour taste I stopped trying to chew through the shell and as the feeling didn’t go away I googled it and ended up her. To dampen the nasty feeling/taste I drank water and (ironically) cashew fruit juice.

    In the end I think I got pretty exposed to the poison in my mouth and lips, but despite that I just got a fat lip and a sore on my lip. It was a bit uncomfortable, but no scarring or anything serious and the sore went away after about a week. I guess I was a bit lucky.

  54. I was a victim, tonight.
    I never really cared for cashew fruit despite living in Nigeria, where we have it abundantly.
    Today, we went for the site work and a few of us decided to go cashew plucking. After the job, I decided to eat it since I’d worked for it.
    The cashew was, well, okay, and then I decided to bite into the nut. On doing so, I heard people yelling at me to stop because it was very acidic and corrosive for the teeth. I almost rolled my eyes, but stopped. Not too long after, the bitter feeling came and then the burning feeling. My mouth was practically on fire!!!
    I rinsed with some water- which we were already short of- and then someone gave me a bottle of water, on hearing about my predicament. I drank sufficient water and then we started our long journey home.
    My lip was slightly swollen at some point.
    Right now, I’ve applied the Nigerian “cure all” oil aka palm oil, on my lips, tongue and mouth. Whenever we have any home accident, poisoning and so on, palm oil comes to the rescue, so I decided to try it this time.
    Fingers crossed on how it will play out. Would be going o bed soon and I hope I’ll be fine, tomorrow.

  55. my experience started two weeks ago..bought some fresh cashew fruit at the market here in the philippines and was told the fruit was good with salt..not much was said to me about how to properly prepare the nut..sadly.
    so i tried roasting them and it didnt go well…the smell and fumes was horrible..i think i did breath some in..i tried cracking the shell open and immediately was confronted by an acrid toxic taste ..mouth got swollen, skin on my fingers got tight took about two days for the reaction to really start and since then it has been an absolute nightmare..frequent trips to the hospital due to anaphylactic symptoms..ive been on steroids for two weeks..and the intense rashes and hives have gone so has the crazy itching.. but if i stop steroids i still experience recurring symptoms..going to see a specialist tomorrow hopefully theyll have had some experience and will long to treat me for..has anyone ever had the symptoms come back after theu stopped meds?

  56. So sorry to hear of the tribulations of all the cashew nut eaters here. I too had been stung by cashew urushiol oil but, believe it or not, I willingly paid (by credit card) for that privilege.

    Let me elaborate.

    I am a Kiwi and was on a flight to Kuala Lumpur some years back when I saw an advertisement in the airline magazine about a skin treatment. It talked about the ability of a cashew extract to burn off blemishes on skin. So a few days after landing in KL I made a bee line to the clinic. There I was met by white-cloaked ladies who convinced me that the cosmetic growths on parts of my body could be easily cleaned up with one or two treatments of this cashew nut oil.

    One of these ladies simply used a cotton bud to dab the oil lightly on my unwanted derma protuberances. And as all the victims of urushiol here have described correctly, this potion stings. The clinic however must have formulated the strength of the oil to a level which was just tolerable.

    Within a few days the skin blemishes had started to dry up and soon fell off.

    I only had a small part of my skin treated as I didn’t trust the efficacy of the technology at that time and it was rather expensive. It did prove that the cashew can possibly have a place in helping to rescue dermatological disasters but my belief is that it works no better than administering any irritant onto your skin. The skin reacts by self-immolation and then eventually drops off.

    The moral of the story is that every cloud has a silver lining. The lining of the cashew nut certainly helps some people to earn a lot of silver.

    All the best.

    Alan Chew
    Hamilton, NZ

  57. Ok guys I love cashew nuts, cashew milk, cashew cheese… And cashew butter. And I’ve been living in Asia for 4 years & traveling frequently to Vietnam where the have some of the best & freshest cashews. I’ve heard about eating the fruit… I’ve read about where the nut comes from… But I had never heard of this poisonous venom! A month ago I came in contact with some sap/ oil while cutting bananas or mango from trees and ended up with a viscous rash that looked (and itched) like poison ivy. All this time and I still have an itch and scar… You think I would learn my lesson! First I am extremely sensitive to poison ivy/ oak… I knew right away when I bit into that nut that something wasn’t right. It’s a few hours later and lips are swelling. It’s the first day of my holiday and somehow I think the whole time I’m going to be miserable! Took 4 ibprofin & vitamin C as a preemptive strike but I feel the itch coming on!!!!!! No one really followed up… How can I get rid of this thing fast?!

  58. Hello everybody!, took me the entire afternoon to find out that I was not the only one to bit that nut.Almost 3 days later and I can hardly open my mouth, what do you do? what kind of ointment can you use, I have been using diaper rash cream on my lips.Can somebody give what to do to get better?
    thank you all!

  59. Beatriz,
    First off, though it may seem/be painful, make sure to wash your face with soap and water. It helps. Then I’d suggest going to a local pharmacy and asking them what they’d recommend for an allergic skin reaction. When I was in Peru, I got some kind of hydrocortisone cream at the pharmacy that, together with washing (I’d been out in the jungle with no running water and was afraid to wash my face because it was so inflamed), made a considerable difference. You might also check to see if there are cashew trees around where you are. My case was exacerbated because I was surrounded by cashew trees (and their pollen!) in the jungle. It will probably take a couple weeks to clear up. at least it did for me. Good luck! My heart goes out to you.

  60. I tried everything I could find when in Cambodia. Thought the Sx we’re peaking at day four,…only to find they cont to worsen for me. Almost 7dAys after eating the raw nut in Cambodia I arrived back in the USA. Almost 50% of my body was then itchy and covered. I had given myself systemic urushoil poisoning. After heading into UMC I was prescribed prednisone. Started to feel relief after 2 days and by the end of the week I was back to normal. I haven’t eaten a cashew since then (March 2015) my favorite but, but I’m terrified I will now be sensitive. That was one of the most miserable experiences for me. Get out on steroids ASAP and you will be fine (:

  61. I just now byte the shell and now my tongue is burning. Please help me what remedies i need to follow. Any advice is greatly appreicated. I just byte it for a min only and immediately spitted out and washed the mouth but since 4 hours my tongues is burning and lips are little red. Please please please give me an advice.

  62. I figured out that it was raw organic cashew nuts bought at Gus’s Grocery store that caused my stomach to burn as well as profuse sweating, flushed face and neck and pins and needles and itching all over my entire body from head to toe like hives without the welts. I ate 1 handful and then had an immediate reaction. I took Peptic Complete and Benadryl which brought some relief. The symptoms lasted for a week before finally going away.
    Then I wanted to be sure what had caused the bad reaction so a month later I ate 3 cashews from that same batch and within 5 minutes my face started getting hot and some itching and stomach burning. I know for sure now that it was the cashews. My guess is that they were not processed correctly.

  63. Oh my! Did the same thing about 2 hours ago! As soon as I felt what you guys did, I researched online & found all this helpful info, so washed thoroughly, even called Poison Control (despite being out of the country). The operator was very nice, but did ask “really?” (not in a sarcastic tone, more in a concerned one) and said to use hydrocortisone on my skin and drink cold fluids. He assured me I’ll be fine. I have an autoimmune skin disease, so I’m praying my reaction will be positive instead of negative & it will actually cure me…trusting God always!
    Thanks to all for sharing your experiences & Matt for creating the blog.

  64. Here…count me on your list. Today only my Mom brought it to show me. But in order to eat cashew it bit that shell. But didn’t ingest the oil, just on my right side of mouth little bit of oil got spread. Burning is there. And my cheek and tongue are feeling weird. I have exam in few days. Is it very much nessesary to go to doctor and have medicine.

  65. I had shared my experience, but don’t see it posted. Anyway, I avoided all the reactions and going to doctor by praying and heeding all the advice posted by others; hydrocortisone for my hands, took some low dose prednisone I had leftover for about a week; additionally drank about a gallon of water, coconut milk, even more of the fruit juice and applied aloe Vera to my mouth area, also swallowed some of it. Good luck!

  66. So for the last summer I got poison ivy for the first time and it seemed to come back once a month even through the winter always on my face and lips. Finally looked up what can cause it and found out cashew have the same toxin. I then realized I have eaten cashews right before every case of rash. I asked the doctor and she said nope it doesn’t look like a nut allergy. So like a dope 4 days ago I decided to test my theory and ate a handful of cashews and I am now once again in pain with blister all over the inside of my throat. So my point is if you had had a serious reaction to raw cashews you need to be careful eating canned ones because it can make you hypersensitive to the tiny bit of oil that maybe left if they are not processed correctly.

  67. Just happened to me too. Drink n spit liter’s after that a coconut oil or moringa oil pulling relieved me from the burnings. Just happened a moment ago let’s see don’t think it ll get worse.

  68. Now part of a club I never knew existed. I too bit into a raw cashew nut two days after thinking that because shell was soft, should be an easy nut to crack. The acidic oil burned my lips immediately and they have felt raw for two days. Now, on day 2 I woke up to a swollen half of upper lip and puffy face especially under my eye. Naturally, I freaked being that I live in a third world country with subpar medical facilities. I popped a healthy dose of Benadryl and put some steroid creme on the rash. Reading all of your stories makes me feel like less of a bozo and more of an adventurer with wounded pride.

  69. A few years ago i roasted some and a really black oil of good proprtions came out of the seeds, but they tasted ok.
    So I thought, two days ago, i would try to roast some more, but roasted it less, to avoid the excess blackening and oil.
    Needless to say, but good thing I roasted a little, I am here, and it is true. My lips got it the most, but i spit the zhit out…
    And I said to myself… “How the fk do they get those roasted cashews to taste so good, when the rest of the nut is so toxic?”
    Long live almonds!

  70. I am in Brazil now and I have the flight back in 3 hour and I just did the same mistake!! now my tongue is burning and my lip is becoming big !
    Thanks for your info, I wish my allergic reaction pass soon :((

  71. Another ‘nutter’ here on holiday in Sao Paulo, Brazil. This morning I was reading about the fruit you should try in Brazil and it mentioned that you should be aware of the peppery taste of the caju nut shell… So guess what? my curiosity won. I even spoke to the locals to confirm that caju is the fruit that produces the cashew nut and nobody warned me! My lips feel sore, my mouth is fine, I ate the cashew nut raw… I’m wondering about what’s coming up.

  72. Same here in Goa 2020.
    There must be some milk, lemon, snake oil, bat balm that helped the ancient ancestors get rid of it…
    Anyone ?

  73. Hello all, I found the Maranon (Cashew Apples) frozen at a Mexican imported foods store in Tennessee. I didn’t actually bite into the nut, but I cracked it open and ate a very small piece of the nut after microwaving it thoroughly. Hopefully I won’t have any systemic effects – btw I found this article of someone getting autoimmune liver disease 1 yr after eating raw cashews: and this very good medical-journal article: (click the “PDF” symbol near the top of the page to see full article).

    It seems that some people have lasting eczema after these exposures too. I have severe, maddeningly itching dermatitus on my hands from cracking the nut, which took 2 weeks to develop and the red sores are spreading to all my fingers. I should go to the doc and get the shot and prednisone pills – thanks to all for that advice.

    I do get relief from a great skin wash by “tecnu” I had from a previous run-in with poison ivy, along with “Caladryl” (calamine with anesthetic). But of course these wouldn’t help inside the mouth.

    I will be so sad if I have allergic reactions to all cashews in the future from this as they’re my favorite treat. And thanks for the warnings about mango skins and pistachios – peace.

  74. Thank you for the post and all the comments! I bit into a cashew nut shell in SC, Brasil 10 days ago. The seed was at the bottom of a both of mixed fruit, so I thought it was there to ‘enjoy’.

    I jumped online and went over a bunch of links within say 10m. One resource said that alcohol can neutralize CNSL so I did that. So I sat with a cup of vodka and rinsed for about 15m.

    The right side of my mouth turned white as I lost the outer lining of skin. But, no swelling, no burns occurred on the lips or tongue or soft tissues. I lost taste on the right side for about 8 days and everyone on the left tasted sour, even water.

    I also had a band of poison-ivy like rash on one leg. That’s about it. No allergic reaction at least nothing apparent.

    Of course, after going through 25 links now I can’t find the article that mentioned using alcohol or I would have posted it here. Best of luck everyone!

  75. Thanks for your comment Michael. Glad you are feeling a little more normal now. Alcohol is a good trick, but hopefully something I’m not planning to repeat personally.

  76. Unfortunately, I am reading this after biting a raw cashew nut with its shell.

  77. Goa 2022. I am reading this after biting it raw with shells . My lips and nose is little itchy. And my tongue has burning sensation. I hope it doesn’t get worse and I am good to go ahead with my upcoming exams.

  78. My partner and I plucked 4 cashew nuts while we were in Indonesia. Back at home in Europe we cracked them open with a nutcracker and a knife and ate the nut bits that were contaminated with the oil in the process of opening the shell. I noticed just a little prickling on the tongue and throat but my partner experienced quite a burning sensation down his oesophagus. We consulted the internet and were alarmed … We gargled with water, I also drank some milk. I spoke to a doctor who said there is not much you can do other than wait and see what happens as he would not recommend taking cortisol just on suspicion. It’s been 5 days and we have no symptoms whatsoever. The burning ceased completely after 2 days and we had no reaction on the hands either. We might have been lucky. Perhaps it makes a difference what type of cashew, how old they are … and obviously the personal sensitivity to the allergic agents. We have avoided mangos and nuts for now and will do so for the next days. Fingers crossed.

  79. Many years later, but I did the same in Thailand 10 days ago. I bit on the shell expecting it would crack open and a nice cashew nut would appear .

    I experienced the same burning sensation and the corner of my lip got swollen (2 days) and had marks / blister like spots (for about 6 days). I did not have any itching. I have had some weird redness on various locations on my body coming and going. But, today, after 10 days (!) – thinking this experience was over – woke up with one eye totally swollen.

    I’ve taken antihistamine from day 1 (still am, was planning to for 14 days). I’m hoping the swollen eye will be a short situation.

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