# Is there a simple test to determine if a mushroom is eatable or poisonous? **URL:** \ **Category:** Factual Questions\ **Created:** [April 25, 2004, 4:47pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925 "2004-04-25T16:47:42Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![CoatOfArms](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@CoatOfArms](https://boards.straightdope.com/u/CoatOfArms)\ **Post date:** [April 25, 2004, 4:47pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/1 "2004-04-25T16:47:42Z")
Like using litmus paper, density, color, smell, sinks in olive oil, etc.? Have 100’s growing in the woods behind where I live. ---
**Author:** ![Yesterdog](https://avatars.discourse-cdn.com/v4/letter/y/d07c76/32.png) [@Yesterdog](https://boards.straightdope.com/u/Yesterdog)\ **Post date:** [April 25, 2004, 4:50pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/2 "2004-04-25T16:50:08Z")
> [@CoatOfArms](#): > > Like using litmus paper, density, color, smell, sinks in olive oil, etc.? Have 100’s growing in the woods behind where I live. I prefer the taste test myself. Actually, if I’m not mistaken, which I probably am, visually. I believe that spots on the dorsal side of the shroom indicate poison. ---
**Author:** ![AndrewL](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@AndrewL](https://boards.straightdope.com/u/AndrewL)\ **Post date:** [April 25, 2004, 4:51pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/3 "2004-04-25T16:51:46Z")
> [@CoatOfArms](#): > > Like using litmus paper, density, color, smell, sinks in olive oil, etc.? Have 100’s growing in the woods behind where I live. No. The only way to be sure is to identify the exact species. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [April 25, 2004, 5:24pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/4 "2004-04-25T17:24:37Z")
I remember being taught in school that identifying edible mushrooms is extremely tricky and that even serious mushroom hunters get tripped up. Basically, the lesson was that you shouldn’t try to do so. Occasionally someone will need a liver transplant after consuming poisonous mushrooms. ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [April 25, 2004, 5:41pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/5 "2004-04-25T17:41:19Z")
> [@Dewey Finn](#): > > even serious mushroom hunters get tripped up. That’s what some of them aim for 😃 ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 25, 2004, 6:12pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/6 "2004-04-25T18:12:55Z")
> [@Ryan K](#): > > I prefer the taste test myself. I’m guessing he wanted what engineers refer to as a nondestructive test. ---
**Author:** ![Wearia](https://avatars.discourse-cdn.com/v4/letter/w/13edae/32.png) [@Wearia](https://boards.straightdope.com/u/Wearia)\ **Post date:** [April 25, 2004, 6:24pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/7 "2004-04-25T18:24:35Z")
No, there is no way to easy tell apart poisonous and edible mushrooms. The only way to do it is buy a book with full color photos and accurate descriptions of mushrooms to positively ID them. And trust me, it is far better to be safe than sorry. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [April 25, 2004, 6:31pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/8 "2004-04-25T18:31:10Z")
I’ve been brought up in a remote place and I spent a lot of time collecting mushrooms. I read a little about them also for this reason. I’m definitely not a reference about them, but I know some little bits. > [@Ryan K](#): > > I prefer the taste test myself. > > Actually, if I’m not mistaken, which I probably am, visually. I believe that spots on the dorsal side of the shroom indicate poison. Nope. There are mushrooms with these spots which are edible, though some are extremely similar in appearance to poisonous species. I couldn’t give you examples, because I don’t know their english names. And you can’t even say that one should avoid the spotted mushrooms if one doesn’t know what they are, because you should _ **NEVER** _ eat a mushroom, spotted or not, if you aren’t 100% certain that you correctly identified it. So, avoiding mushrooms because they have some feature or another which is found in some well-known poisonous species (like the spots, or a “collar”, become green when broken, etc…) could somewhat reduce the risk, but wouldn’t remove it, by a long shot. Plenty of poisonous mushrooms don’t display such features. Besides, some features can be noticeable when the mushroom is young and dissapear when it matures. I’m going also to insist on the fact that many species of eatable mushrooms are very similar in appearance to poisonous ones. There’s at least one specie I personnally _believe_ I can tell apart from a similar poisonous (though not deadly) one but would never pick because I’m not absolutely certain. So, one shouldn’t try to collect mushrooms with for instance only a book with pictures as reference. You should learn how to recognize an edible specie with people who are already familiar with them. And such people, apart experienced mycologysts, are generally only familiar with a limited number of species (note that many people collecting mushrooms believe that some species are poisonous while actually they aren’t. But it’s certainly way better than the contrary). As for the OP, AFAIK, there are no reliable way to determine if a given mushroom is poisonous or not. There are many different toxins, with many different adverse effects (from diarrhea to liver destruction, for instance), so no simple test can tell them apart. Tests sometimes suggested are just plain crazy and bordering magic belief. Some tests perhaps would allow to identify _some_ poisonous species but definitely not all. Even, say, feeding your dog with them wouldn’t be a reliable test, since some mushrooms are toxic for some animals and not for others. Finally, I would mention that there are mushrooms which are poisonous when eaten raw, but edible (and even delicious) when cooked, because the toxins are destroyed at high temperature. There are also mushrooms which aren’t poisonous, but aren’t edible, either, because they have a displeasant taste, or a weird texture. Just in case I had not been clear enough : you should _ **NEVER** _\* collect a mushroom that you aren’t familiar with. Forget about any “test”. If the OP wants to gather these 100’s of mushrooms behind his house, he should probably join a mycology association, and go out with them collecting mushrooms, learn how to recognize them, and then only begin collecting them by himself. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [April 25, 2004, 6:31pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/9 "2004-04-25T18:31:34Z")
We went to a nature hike for mushroom identification a couple of years ago. The guy conducting the hike said that if he is ever unsure, he places a small portion under his tongue. If his tongue starts tingling or going numb, it’s a poisonous variety. But this is someone who has a lot of experience with this sort of thing. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [April 25, 2004, 6:49pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/10 "2004-04-25T18:49:32Z")
> [@clairobscur](#): > > Finally, I would mention that there are mushrooms which are poisonous when eaten raw, but edible (and even delicious) when cooked, because the toxins are destroyed at high temperature. > . Just in case I wouldn’t have been perfectly clear, what I meant is that there are _some_ toxins found in _some_ poisonous species which are destroyed at cooking temperature. Definitely not that _all_ poisonous mushroom’s toxins are destroyed at high temperature. A morel is safe once cooked. A death-cap definitely isn’t. ---
**Author:** ![CoatOfArms](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@CoatOfArms](https://boards.straightdope.com/u/CoatOfArms)\ **Post date:** [April 25, 2004, 6:53pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/11 "2004-04-25T18:53:33Z")
> [@clairobscur](#): > > … Even, say, feeding your dog with them wouldn’t be a reliable test, since some mushrooms are toxic for some animals and not for others. … Damn, my wife’s dog … :mad: ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [April 25, 2004, 6:59pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/12 "2004-04-25T18:59:00Z")
> [@Chefguy](#): > > We went to a nature hike for mushroom identification a couple of years ago. The guy conducting the hike said that if he is ever unsure, he places a small portion under his tongue. If his tongue starts tingling or going numb, it’s a poisonous variety. But this is someone who has a lot of experience with this sort of thing. Maybe it’s true for some mushrooms, but I wouldn’t rely on this “trick”. The adverse effects of some mushrooms become noticeable only a long time after they’ve been _ingested_ , so there wouldn’t be any consequences at all if you put it under your tongue for a brief moment. It wouldn’t prevent you from dying if you actually ate them, though. This guy probably knows what he does (though perhaps not), but he probably only uses this method for specific mushrooms he’s unsure about, knowing that the particular poisonous mushroom he could mistake for the edible one has such an effect. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [April 25, 2004, 7:01pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/13 "2004-04-25T19:01:16Z")
> [@CoatOfArms](#): > > Damn, my wife’s dog … :mad: Sorry, but I read some stories about people doing that (having unknown mushrooms “tested” by a pet). So I thought I would mention it. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [April 25, 2004, 7:05pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/14 "2004-04-25T19:05:41Z")
> [@clairobscur](#): > > This guy probably knows what he does (though perhaps not), but he probably only uses this method for specific mushrooms he’s unsure about, knowing that the particular poisonous mushroom he could mistake for the edible one has such an effect. That sounds about right. ---
**Author:** ![chukhung](https://avatars.discourse-cdn.com/v4/letter/c/e79b87/32.png) [@chukhung](https://boards.straightdope.com/u/chukhung)\ **Post date:** [April 25, 2004, 7:14pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/15 "2004-04-25T19:14:50Z")
This [page](http://www.icomm.ca/survival/245fil.don/mushroom.htm) seems to have some good information about mushroom poisoning. After reading it, I think I’ll take along an expert when I go mushroom hunting and then wait at least a couple of weeks to see how he’s doing before I eat what I collected. > [@](#): > > [A long list of gruesome ways to die after eating mushrooms deleted…] > > The final type of protoplasmic poisoning is caused by the Sorrel Webcap mushroom (Cortinarius orellanus) and some of its relatives. > > This mushroom produces orellanine, which causes a type of poisoning characterized by an extremely long asymptomatic latent period of 3 to 14 days. An intense, burning thirst (polydipsia)and excessive urination (polyuria) are the first symptoms. > > This may be followed by nausea, headache, muscular pains, chills, spasms, and loss of consciousness. In severe cases, severe renal tubular necrosis and kidney failure may result in death (15%) several weeks after the poisoning. Two weeks after you’ve eaten some mushrooms, are you going to remember exactly what they look like when you show up at the emergency room with chills, spasms and excessive urination? Another fun 'shroom listed on that page is the inky cap mushroom (Coprinus atramentarius). Apparently it’s generally considered edible. Except that it contains a compound that interferes with your body’s ability to break down alcohol. If you drink within 72 hours of eating an inky cap, you can expect “headache, nausea and vomiting, flushing, and cardiovascular disturbances that last for 2 - 3 hours.” Say what you like about poisonous snakes, at least when you’re bit by one you immediately know you’re in trouble. With poisonous mushrooms, on the other hand, it looks like it can be hours or even days before you realize that you’ve screwed yourself royally. ---
**Author:** ![Tentacle\_Monster](https://avatars.discourse-cdn.com/v4/letter/t/ba9def/32.png) [@Tentacle\_Monster](https://boards.straightdope.com/u/Tentacle_Monster)\ **Post date:** [April 25, 2004, 7:30pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/16 "2004-04-25T19:30:40Z")
I recommend the Audubon Field Guide to North American Mushrooms. All the mushrooms are photographed, have detailed descriptions, are described as edible/inedible/poisonous species, and IIRC the guide even has recipes for the better edible ones. That being said. stay away from LBMs (Little Brown Mushrooms). There are a lot of species that look alike, and many of them are poisonous. ---
**Author:** ![quiltguy154](https://avatars.discourse-cdn.com/v4/letter/q/ad7895/32.png) [@quiltguy154](https://boards.straightdope.com/u/quiltguy154)\ **Post date:** [April 25, 2004, 7:37pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/17 "2004-04-25T19:37:43Z")
Personally, I’d go hunting/collecting with someone serious about the whole thing, but not if they’re under 60 years of age. A saying in mycological circles goes, “There are old mushroom collectors, and there are bold mushroom collectors, but there are NO old, bold mushroom collectors.” ---
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [April 25, 2004, 8:21pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/18 "2004-04-25T20:21:04Z")
I had a book giving advice to hikers. It had a general procedure for testing edibility of any unknown plants (not only mushrooms). 1. Rub onto skin (the inside of your arm for example). If it doesn’t get irritated, proceed to 2. 2. Rub onto tongue. If it doesn’t cause numbness, swelling or anything strange proceed to 3. 3. Take a small bite. If after about an hour you feel fine, then it is most probably safe to eat. ---
**Author:** ![Danalan](https://avatars.discourse-cdn.com/v4/letter/d/76d3ee/32.png) [@Danalan](https://boards.straightdope.com/u/Danalan)\ **Post date:** [April 25, 2004, 8:35pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/19 "2004-04-25T20:35:10Z")
Any truth to the old saw about mushrooms requiring more calories to eat and digest than are provided by eating and digesting them? On a related note, does any foodstuff have a negative food value? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 25, 2004, 8:57pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/20 "2004-04-25T20:57:58Z")
The only reliable way to identify poisonous or edible fungi is just that - _identify_ the species against a good reference guide (for the UK and northern Europe, I heartily recommend Roger Phillips’ book _Mushorooms_) - the book will describe size, colour, smell, taste\*, habitat, season, associated trees, soil type etc - for a positive ID (essential if you’re going to eat the thing) you must match ALL of the descriptors (\*except taste, which I don’t recommend - even the most deadly species have a description of the taste in the text books, as it is possible to taste a small piece of them and spit it out after a few seconds, BUT I DO NOT RECOMMEND THIS - preliminary identification by all descriptors execpt taste is fine.) To put things in perspective, (for the UK, but probably similar elsewhere) there are thousands upon thousands of fungus species, there are only a couple of dozen species that are deadly poisonous that you would actually be at risk of picking, there are probably about fifty species that are both edible and really tasty, the remainder of species fall into the following sorts of groups: -Edible but incredibly rare or overlooked -Poisonous but incredibly rare or overlooked -Inedible due to unpleasant texture or taste -Too small to be worth gathering, or even to notice. **CoatOfArms** - you don’t say where it is in the world that you live, but if the mushrooms are there now, this narrows the process of identification greatly, because most fungi produce fruiting bodies (the bit we eat) in the autumn - comparatively few fruit in the spring. If you were in the UK (which seems not to be the case) and the mushrooms were largish, firm-textured, entirely white/cream in colour (even the gills), smelling of stale bread, growing amongst leaf litter in beech woodland on chalky or stony soil, and appearing at about the same time as the bluebell flowers, I’d be confident of an ID of _Tricholoma Gambosum_ - St George’s Mushroom, which is edible and good, but I don’t think it appears in America. Even so, a spring-appearing fungus should be easy to ID. [Next page](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925.md?page=2)