Though cashew nut oil from the shells is not safe to consume, it does have uses. It may be distilled and used to line brakes to provide friction, or may make up one of the resins in epoxy finishes and coatings. Touching these extractions from raw cashews may create rashes, but this is less common, since the oils and resins made from them undergo extensive processing.

The cashew tree is a New World food, and it’s certainly a testament to the ingenuity of New World races that we even eat “raw” cashews. At some time, pre-dating written history, the people of Brazil figured out that the fruit surrounding the cashew “nut” could be eaten, but the shell could not. Also, early Brazilians were able to understand that the nut could be used when steamed or cooked. This may have been a trial and error process, with many people getting ill from error testing, but it ultimately brought us to the enjoyment of one of the most popular nuts, now grown in many places throughout the world.

This is why we don’t eat strictly raw cashews. Even the “unroasted’ varieties are steamed to release urushiol from the nut and make it safe to eat. Certainly, those raw cashews sold as raw have been processed to remove urushiol, so there is no danger in consuming them. As nuts and seeds go, safely prepared cashews actually cause very few allergies, especially when compared to nuts like walnuts or legumes like peanuts.

Urushiol is the same chemical found in poison ivy , and it is present on the leaves of the cashew tree as well as in the raw cashew shell. Processing raw cashews can be a laborious and nightmarish ordeal, and people who work in cashew processing plants tend to exhibit greater allergies to cashew shells over time. There is a high incidence of skin rashes among people who either harvest or process raw cashews. Greater sensitivity to urushiol can lead to extreme allergic reaction when raw cashews are ingested, and anyone allergic to poison ivy could potentially have a fatal reaction to eating true raw cashews.

Unless you happen to work in a cashew plant or pick cashew apples, it’s unlikely you’ll encounter completely raw cashews . The so-called raw cashews sold in natural food stores are not exactly raw, but instead are steamed. It is the case that the double shell surrounding the raw cashew, which is technically a seed and not a nut, contains urushiol , a resin that can create significant skin rashes, and can be toxic when ingested.

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Discussion Comments

anon997673 February 11, 2017 Some of the problems I am hearing here are probably due to a condition known as diverticulitis. These sacs in the transverse colon become inflamed when small particulate matter, such as chewed bits of cashews create an infection. It probably doesn't help that the cashews contain something irritating. The clue here is with the pain starting on the left, just below the rib cage.

anon996684 September 27, 2016 Cashew nuts and the apple of the cashew are not poisonous. The only place where urushiol exists is in the shell around the seed. The steaming or boiling opens the shell without exposing the seed to the resin.

anon994557 February 18, 2016 Another possible health concern. I had some kind of heart congestion feeling, for lack of a better description, it made it hard to sleep for a few days and had me worried. I am very good with my diet, eating vegan, mostly organic and virtually only real food, (no ingredient label). I am also very athletic but don't overdo my workouts. So I got this strange feeling in my chest -- not a pain, but like my heart had enlarged and was uncomfortable. The only two new things I had added to my diet were new, cheaper, raw cashew pieces from the health food store bulk bin, and I changed over from a regular coffee brewer to a french press. A naturopathic doctor said sometimes a nerve in the stomach area can be triggered causing a person to think it is the heart giving a problem when in fact, something is irritating the stomach. I just went back to organic brewed coffee today so I don't know if it was too much coffee grounds from the french press irritating the nerve or a poorly processed cashew raw bulk cashew. I had never noticed this sensation before I bought that bag of bulk cashew pieces. It scared me a bit. After reading this article, I am starting to think it is more likely the poorly processed cashews that triggered a nerve in my stomach, causing my heart to feel like it was having problems. I will look into this further. I just came across this article and want to share my beginning observations while I have a moment. I am very food aware and exercise every day, so this unusual situation made me look for cause and effect. For the last week, with no coffee or bulk bin cashews, I have not had that strange feeling in my heart area and my heart feels normal again.

anon990081 April 5, 2015 For the last week and a half, my lips have felt weird, my mouth has felt raw, and my butt has had a really itchy rash resembling poison ivy. I'm a medical professional, so I've been trying to diagnose myself. Antihistamines and steroid creams (on my butt) seem to help, but it all comes back if I stop taking the meds. I tried to think of what was different about the last two weeks. I narrowed it down to new laundry detergent and eating a lot of cashews lately. After reading this, I'm positive it's the cashews! I've never had any nut allergies, but I'm very allergic to poison ivy. Glad to find out I'm not the only one having this bizarre reaction! No more cashews for me.

anon980160 December 2, 2014 Just ate a can of planters cashews a couple days ago. Now my lips, eyes, butt, etc, all itch. I am severely affected by poison ivy. I have never had a problem and I must have eaten a ton of cashews in my life but there is no doubt they are the cause of my current suffering.

anon968186 September 1, 2014 I love raw peanuts and cashew nuts but, guaranteed, when I do eat them I suffer.

anon963529 July 30, 2014 I had the experience of trying to roast raw cashew nuts in cooking oil in an enclosed area, in a room rather than outside because there were cashew trees in the yard and I figured I could save money by roasting the nuts myself rather than buying them commercially. I sure learned my lesson. I found out it was compared to burning poison ivy. Now I can't even eat a Planters cashew nut because I am too sensitized to the residual cardol oil in even the properly roasted nuts.

ibm8086 July 25, 2014 Wow. I am so surprised to hear this. I grew up around the cashew trees. As young children we liked the fruit as well as the nut. We cut the nut open when it was still green or when the nut hardened to the hard grey shell. I have never heard of someone having a bad reaction to the oil when the hard nut was cut open. There was never any caution paid to the oil. The green nuts did not have this oil. One thing though: when we roasted the dried nuts over the open fire, we never let the chickens get too close because we were told they got something that looked like a bird flu. But we inhaled the oil filled smoke for hours on end. And broke the roasted shells with a piece of wood and bare hands and used those same bare hands to put the edible portions in the mouths. I still like the taste of the cashew nuts, raw or roasted. I don't remember what the oil tasted like; it was so insignificant.

anon949370 May 5, 2014 The main risk with unroasted cashews is they contain "oxalic acid", which can cause kidney stones. I'm not guessing. So beware.

anon945695 April 14, 2014 Can anyone tell me how to process the cashews I have growing in my yard? I understand the apple is safe, but I want to prepare the nuts to eat safely.

anon355598 November 18, 2013 I ate a handful of salted, roasted cashews that I bought at a supermarket last night and had a flu like reaction, including abdominal discomfort and vomiting. I've eaten plenty of cashews in the past, even made partial meals out of them when camping. I'm wondering if somehow whoever manufactured these cashews somehow did not do the processing correctly.

anon353614 October 31, 2013 So, I hadn't ever heard of a cashew fruit (although familiar with the nut) until my husband and I moved to the Caribbean. I've eaten tons of them it feels like and never once had any adverse reaction. Granted, we have never bought them with the gray part attached. I am certainly curious about how they remove the gray part in such a way that the cashew apple is safe to eat. Also, it's good to know that if I ever see any with the gray part still attached, I should probably forgo that purchase.

anon344315 August 7, 2013 I had a bad reaction to poison ivy when I was 19. It resulted in blisters all over my body, including my mouth, testicles and anus. Unbelievably horrible, although I must say that a hot bath felt better than an orgasm. Anyway, I noticed a few years ago that raw cashews trigger a poison ivy-like reaction, and recently, roasted cashews did the same thing! Interestingly, I only get a reaction on my lips, the inside of my mouth, testicles and anus! This has happened a couple of times with raw cashews found in the supermarket and only once recently with the roasted variety.

anon318968 February 10, 2013 I bought some cashew fruit in the Philippines. The trees abounded in the area. I asked if they were safe to eat and they said no problem. I ate the yellow fruit and it was a bit sour. Then I thought I would eat the nut and cracked the shell with my teeth. A tingling started on my lips and throat and lasted for hours. I'm am glad to read it's probably not going to get worse, but am alert.

anon316665 January 29, 2013 I bought a package of cashew fruit like pictured above. They really should put a warning on these things. I tried to get the nut and tried to cut it open with a knife. The resin-like liquid inside the nut spilled on a couple of fingers in my left hand broke out in a burning rash. My lip got a tiny burn which healed quickly. Unfortunately, a rash has spread to other parts of my body which weren't originally in contact with the cashew, like my arms and leg. I used to be really allergic to poison ivy when I was a kid, so after reading this article, it made sense that I would react the way I did. So the lesson to be learned is forgo the raw cashew fruit and nut combo. It isn't worth the trouble. Buy cashew nuts from the store instead.

anon314339 January 17, 2013 Who in their right mind goes around biting random nuts while on vacation? And wow I never heard so many people talk about their itchy butts. Lesson is, stay away from weird crap. If you want cashews, buy Planters.

anon280923 July 20, 2012 The process in our factory is: first, put the raw cashew nuts at 100 Celsius for 15 minutes. Second, remove the shells (machine or manually). Third, dry the kernels for 8-12 hours at 80 degrees Celsius. Fourth, but the kernels in a humidifier for four hours. Fifth, remove the testa (layer that cover the kernels) and sixth, go through the re-drying process for the nuts two hours and 50 Celsius. After this process, you can eat the cashews safely, but it will still cause allergies if you are allergic.

anon268849 yesterday My daughter ate a handful of mixed nuts at a friends party recently. Within minutes, her eyes started swelling and tongue had a lump on it. I picked her up and within 10 minutes, she had swelling of her face and by the time got to the A&E, she developed severe red itchy rash started on her head and gradually spread down to her feet within an hour. They gave her antihistamines with no relief, and then moved onto steroids which stopped the itchiness. After couple of hours under observation, we were about to go home when she felt dizzy and low blood pressure. What a nightmare! The rash disappeared overnight, but the swelling of her face lasted three days (can only compare this to pics I've seen of ladies allergic to hair dye). She had crunchy nut cornflakes for breakfast and has had nutella before but not really cashews as far as I know. A very bad nut; I can't like them anymore!

anon267891 May 11, 2012 In India, I found a cashew tree, and although I could tell the nut wasn't fully formed, I decided to try it. It was hell. My lips and mouth immediately went on fire and no amount of water, mints, etc., etc. could quench or get rid of the pure acid burn and taste. I'm not normally susceptible to allergies/or nuts, so these damn things are completely poisonous. The pain, swelling and god awful taste lasted about four days.

anon264175 April 26, 2012 All raw nuts and seeds have enzyme inhibitors which are only removed by soaking in water. Until this is done, they are indigestible. Cashews are toxic whether they are soaked or not. Cooking anything over 115 degrees kills almost all of the nutrients and enzymes in any food and is therefore useless to the body. In fact, your body will react to cooked food as though it wasn't supposed to be there and sends white blood cells to the invader instead of being available for cleaning up the body's toxins they are there for.

anon260154 April 9, 2012 The oil from a roasted cashew got on my lips and hand and now the skin is all gone. Go figure.

anon256064 March 20, 2012 I assume the "somewhat good news" is that you are not going to die? I never try a food that is unfamiliar to me without finding out everything I can - lots of allergies.

anon255381 1 hours ago I have been eating cashews from the "bulk foods" at the local QFC where I live and a few days ago I developed a severe pressure in my eyes that was very painful, had the itchy anus area and last night I awoke while having a bowel movement on myself! My bowels just let loose while I was sound asleep of a soft watery tan mixture, very, very, very unpleasant! I am done with cashews forever and am going into that store today and telling them what those cashews did to me!

anon236565 December 23, 2011 Completely by accident, a friend of mine mentioned that he has an allergic reaction to cashews when I offered him some the other day. He said "They make my anus itch." I laughed but then realized that I had an issue with severe anal itching over the last couple of years and could not figure out what was causing it. It had not bothered me recently. I told him I guess I would do a controlled test to see if that was my issue. I ate five or six handfuls of cashews and sure enough within 36 hours of eating them my anus was itching like crazy. So far it has been itching for two and a half days and counting. I'll stay away from those from now on!

anon229316 November 13, 2011 I was in Venezuela 20 years ago and was looking at renting a house which had some tropical fruit trees in the backyard. One, I was told was a cashew tree. I pulled off a fruit and bit into the nut end to open it before being warned. It was bitter and tingly and I spit it out immediately and washed out my mouth. The next day when I looked in the mirror, I had a black perfect circle the size of a dime on my face where the juice squirted. The ER said it was an insect bite. But the skin died and fell off. Another layer did the same thing. This went on for weeks.

anon205534 August 12, 2011 My husband actually works in a place that processes raw cashews and he brought some home for me. He told me to look on line how to roast them, and when I googled it, this came up. He has been eating raw cashews for weeks now! If he dies, I'm going to kick his butt!

anon198141 July 19, 2011 This is a pretty good article, but the writer may have slightly limited experiences as a gourmand. Chances most certainly can be very high that any one of us may meet a truly raw cashew face to face. In most Latin or Caribbean grocery stores, for example, raw, frozen cashew fruit is often available with the cashew nut still attached. So, in a world that is becoming increasing adventurous food-wise, chances are you will discover a whole cashew fruit one day. That said, my word of advice is to take a pass on frozen. While cashew fruit is sweet, creamy, and very enjoyable when fresh, and certain brands of the bottled juice may even become a favored comfort drink, the experience of eating defrosted cashew fruit is akin to chewing on a frozen washtowel that has been dipped in something slightly spoiled, only slightly sweet, and very mouth puckering (it's not actually tart--the puckering happens on your palate, which may peel slightly). You may get rid of the texture in a smoothie, but not the taste. And as for the experience of cracking into that cashew nut? Your hands and fingers (and lips, eyes, or any other body part you touch) will burn terribly and peel perhaps a dozen times or more before they completely heal. My advice, if you're feeling very adventurous, is to try the bottled cashew fruit drinks (read the ingredients and grab one that is natural) and, if you are lucky enough to find them, the cashew sweets that come from many Caribbean islands, like the Dominican Republic. These usually consist of large chunks of cashew fruit in sugar syrup, sometimes also swirled with a bit of dulce de leche (yum!) Be mindful, but certainly try it!

anon191433 June 28, 2011 Having read some of the posts here and the reactions people get make me wonder why we even eat them at all? I have eaten a whole can or bag of cashews in on sitting and never had any reaction beside my poop turning a light shade of tan. I guess I'm just fortunate! As for the itching, sore or swollen anus, maybe you're eating them from the wrong end?

anon185994 June 14, 2011 Even roasted cashews cause me problems. I had an Indian sauce which must have contained cashews. I have had an irritated anus for almost a month. It is bleeding and itchy. I am severely allergic to poison ivy. It is too bad; I love cashews.

anon177931 May 19, 2011 I am extremely allergic to poison ivy! If you have ever seen a picture of a pine tree that's been scored for collecting sap for making turpentine, that's how bad the skin lesions can get! I had to stay home for a week, taking several cold showers a day! Hot showers just makes the injury worse! And the pain, internally as well as externally is like having a million paper cuts! And then someone pours salt on the cuts! See anaphylaxis and anaphylactic shock! So, in a nutshell (no pun!) stay away from raw cashews!

anon165133 April 3, 2011 I live on an island in the caribbean, and found a yellow fruit with a nut attached to the outside, pulled it off thinking it was a cashew, tried to get the nut out, bite, cut, pliers, slimy thing, but through determination, got the seed out. tasted the thing, not bad not good. Now just waiting to see what happens. seem way easier to just buy them processed, and as hard as those rascals are to get out of the shell. Nine bucks a pound is cheap.

anon164529 April 1, 2011 My brother brought a raw cashew seed for me in my office to taste. he told me that i should roast that cashew before eating, but then he didn't tell me that the shell of the cashew is highly acidic and can irritate skin. Since i don't have fire or oven i tried to remove the shell in my mouth when suddenly i felt a burning sensation. i ran to the faucet and wash my mouth. i looked at my mouth in the mirror and i notice that my lips burned and turned white.

anon159340 March 11, 2011 I've never had any nut allergies, and am very resistant to poison ivy. I eat lots of raw almonds, and wanted to try cashews. A friend got me cashews from the Asian food store he goes to. The nuts were very white, so I assume raw (not roasted). I was eating lots of the nuts, and after a few days started having massive gas, bloating and stomach pain. I didn't know the cause, and kept eating the nuts over a week or so. I finally did some research and saw the possible connection to raw cashews. I've since stopped, but that was months ago. I'm still having flare-ups, and have bloating most of the time. I've logged my food intake recently, and it seems there's not specific food which causes this, but having had peanut butter a couple days ago, I had a big flare-up that afternoon. Is it possible that, if I damaged my stomach from eating too many cashews, that it's permanent? I was considering Aloe Juice to try and repair, and my gastroenterologist had no suggestions.

anon155292 February 23, 2011 My wife and I took a trip to costa rica where we found some cashew trees. I asked the guide and she said the fruit was safe to eat. It tasted a little like apples. I used my mouth to crack open the shell to try the cashew nut. For the rest of the day my lips and fingers tingled. I've never had a poison ivy reaction, but at the time that's what I imagined poison ivy would have felt like. In fact, I think I'm one of the luck ones with high tolerance to poison ivy. It sucked for a day, but then I was fine.

anon154686 February 21, 2011 I don't seem to have a problem eating nuts not raw, but if I have considerable quantities I suffer from stomach pains, sometimes diarrhea with lots of gas, I also get light headed and feel sick. This seems to happen with any nuts I have but I get the biggest reaction from peanuts and cashews. I've never had symptoms of anything in the past from any nut in small quantities. Someone mentioned an itching anus symptom, which funnily enough, I have had come and go over the last two years and I had no idea why. I guess I'll stop eating nuts for a long while.

anon149394 February 4, 2011 My reaction to cashews is a fairly severs rash on my hands. This happened last month, couldn't understand it because I am careful to check for them. Turned out the culprit was the pumpkin soup in the prepared foods section of Whole Foods! I never thought to look at the ingredients of pumpkin soup! Lesson: always check ingredients, especially when eating out!

anon146253 January 25, 2011 Just so you know, if you are highly sensitive you may react to even commercially available cashews in the U.S. If I eat cashew butter, my lips break out in a blistery, tingly rash, I get gas and an upset stomach, my anus itches, and I have headaches and feel tired. I haven't had this reaction to commercially available cashew nuts, but just the cashew butter. I can only assume that there is some small amount of the oil contaminating the butter. I am pretty sensitive to poison ivy/oak as well, but I have no other food allergies or sensitivities (haven't messed around with mango skin, which they say can cause the same reactions as cashew because it is in the same family).

anon143525 15 hours ago I eat raw cashews all the time with no problem.

anon140633 January 8, 2011 I ate some 12 hours ago. I thought I was going to die. The pain in my stomach area was the worse pain I'd ever felt in my life. It felt like I had swallowed acid. I feel slightly better today now the pain has finally gone. I will never eat white cashew nuts again.

anon136119 December 21, 2010 I ate some roasted cashews and experienced everything you guys are complaining about. I suspected it, because I didn't get to eat anything else before falling severely ill. Severe sinus pain and terrible intestinal pain, accompanied by very bad smelling excrement.

anon128394 November 19, 2010 I'm a large, strong, and thick-skinned person. I found a cashew fruit, frozen, at some major grocers in southern California. The nut, growing out of the bottom, is surrounded by a slimy juice, which blistered only the outside of my lips without scarring. I didn't notice any trouble inside my mouth, throat, or stomach. The same, major brand was found to carry hepatitis, several months ago. While I like to try new things, I had no idea I was taking a risk. A slippery sap seems to be the primary culprit. This collects inside of the shell, and around the nut. It was drawn-out simply, before pre-industrial times, and the nuts were eaten in sufficient quantity to make a form of Marzipan. Whites made the fruits into an alcohol. Maybe, people suffering from ongoing exposure were already predisposed to allergy.

anon87445 May 30, 2010 did anyone have symptoms of sore mouth and gums and headache?

anon82469 May 6, 2010 Must never eat “raw” cashew nut, just soak and cook it. I ate cooked cashew nuts before.

anon63058 January 30, 2010 Ate a cup of cashews, bought raw from the Chinese at $6/lb, I put them in the oven for a minute to roast. I have weird needle sensations in the skin of my left hand. go figure.

anon62106 January 24, 2010 I ate 100 gram raw cashew nut at night.I had vomited next day morning where I found it containing only a mixture of cashew and bile extract tasting bitter. -Debdeep, India.

anon61765 January 22, 2010 I bought some raw cashews from JG's health food store the other day, they were on offer (I wonder why?). I ate about half a cup full of them the other night and last night. I've had awful diarrhea ever since and had constant stomach pains early this morning, felt like acid was burning through my stomach lining, it was so bad! First time I've had "raw cashews" and the last. I have no doubt whatsoever they were the problem, nothing else new. Starting to feel better now I've stopped them.

anon60775 yesterday Anon36391, the exact same thing happened to me! It was horrible and I thought I was crazy! It took a while before I figured it out but I stopped eating raw nuts all together and haven't had another incident since.

anon47680 October 6, 2009 I would be so ticked off if I cannot eat raw cashews. All my life I have been eating it. Yes it is very tasty. Worth all the high cost.

anon47207 October 2, 2009 My husband ate a handful of trail mix at the Waldorf Astoria in New York during a conference while he was away on a business trip. It was part of the food presented by the conference. In the trail mix were raw cashews. He did not know they were raw, nor did he know he would was allergic to raw cashews, never having eaten them before. He ate only two or three pieces and his body broke out in blisters inside and out. The ones outside were all over his body and as large as the palm of my hand. They would burst and leak through his pants so that it looked as though someone had thrown water on him. The dermatologist figured out what had happened, because my husband is also highly sensitive to poison ivy. Raw cashews can be a big problem.

anon46788 September 28, 2009 I ate a bunch of raw cashew nuts bought from a health food store and broke out in a horrendous case of hives that were shaped like large white donuts with a large dark red center. My feet were so swollen, when I awoke in the morning I thought I had gone to bed with boots on. I am also extremely allergic to poison ivy. Apparently steaming cashews to remove the shell doesn't neutralize the toxic shell coating.

anon39936 August 5, 2009 cashews available in stores are not poisonous. Ajay

anon36391 July 12, 2009 I was recently on a raw food diet and bought 'raw' cashews from the health food store to add variety to my raw diet. I loved the way they tasted - so addicting! On the first day I ate 1/2 lb of raw cashews (throughout the day) and woke up in the middle of the night w/extreme stabbing pain in my lower left abdomen. At first, I thought I ate too much w/o drinking enough water. So the next day, I ate about 1/4 lb of raw cashews and drank plenty of water while eating - water did not help. Again, I woke up w/extreme stabbing pain in my lower left abdomen. The third day, I ate no raw cashews and had no pain. Now, what I'm about to say is embarrassing to say the least, but may be important to others experiencing the same thing, so here goes: As mentioned above, cashews are part of the poison ivy family and I think the raw cashews I bought were poorly steamed because my anus (butt hole) is really really itchy especially right after I go to the bathroom. Yes, I know how disgusting this sounds, but I promise you it's true. So far it's only been this way for 3 days and seems to be getting better, but the only thing I can attribute it to is raw cashews. To conclude, my advice to others about eating raw cashews, which by the way cost $9/lb where I live, would be to forgo these nuts.

aline May 26, 2009 Just came back from a 2-day hospital stay because Thursday night I handled a raw cashew to see what was inside of it. My husband and I ate the raw fruit. Then, I thought we should eat the nut! I could not opened it and finally threw it away. I will never handle another raw cashew! The next day my eyes started to swell, my nose, my lips etc...I went to the ER and they admitted me immediately. It was the only new food that I had that week.

anon26560 yesterday I ate one. Googled it to make sure I'm not going to die. Because it feels like it. Thanks for the somewhat good news.

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