# 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:** 2
**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, 8:59pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/21 "2004-04-25T20:59:41Z")
> [@Dog80](#): > > 1. Take a small bite. If after about an hour you feel fine, then it is most probably safe to eat. Is this advice intended for survival situations where it’s either eat something or die of starvation? An hour seems awfully hasty when dealing with mushrooms you’re not absolutely sure of. In addition to sorrel webcaps which can be eaten with no symptoms for three days or more, the page I linked to previously, says that the poison in deathcap mushrooms (Amanita phalloides) “is characterized by a long latent period (range 6-48 hours, average 6-15 hours) during which the patient shows no symptoms” and the poison in false morel mushrooms (Gyromitra esculenta and G. gigas) has a " latent period of 6 - 10 hours after ingestion during which no symptoms are evident." In 1988, five people in Oregon ate some stir-fried Amanita phalloides and at least three had to get liver transplants. ---
**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, 9:04pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/22 "2004-04-25T21:04:53Z")
> [@Dog80](#): > > 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. I’ve seen this advice too, but it is dangerous, for example, in cases of poisoning by _Amanita Phalloides_ (the Death Cap fungus - so poisonous that a single fruiting body is enough to kill a family, yet reported by dying victims as actually quite tasty) the onset of symptoms is typically delayed by 6 to 24 hours. It is an absolutely horrific death. The only time to experimentally eat something that you haven’t been able to otherwise positively identify as safe is when you are going to die anyway of starvation, in which case you’d be better off eating insect larvae than mushrooms. ---
**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, 9:07pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/23 "2004-04-25T21:07:04Z")
> [@Dog80](#): > > 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. DO NOT give this kind of advice. Read the link provided by \*\* chunkhung \*\*. Poisoning symptoms can occur _days_ after the ingestion. And it’s in particular the case for the most lethal Deathcap. ---
**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, 9:14pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/24 "2004-04-25T21:14:03Z")
> [@Mangetout](#): > > 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, . That’s true but : There are numerous species which, though not being lethal are still toxic. More importantly, the number of species doesn’t matter as much as how common they are. Amanitas are very common mushrooms, at least over here. ---
**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, 9:30pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/25 "2004-04-25T21:30:07Z")
Quite, but the amateur fungus collector need only familiarise him or herself with a couple of dozen really good edible species and a handful of poisonous ones (especially those where there is any danger of confusion with the edible ones) - the rest can simply be treated as scenery. ---
**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, 9:35pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/26 "2004-04-25T21:35:09Z")
> [@Mangetout](#): > > , 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. I looked for pictures of the thing (that I didn’t know, by the way), but found on one site a warning stating that it could be mistaken for the “dangerously poisonous” Red Staining Inocybe which can grow during the same period. I looked too at pictures of the latter, and it didn’t appear that similar to me, but still. That’s why I would be extremely reluctant to advise people to rely on books and pictures, without help from an experienced collector (and there are mycology associations or groups organizing excursions). ---
**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, 9:48pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/27 "2004-04-25T21:48:05Z")
> [@Mangetout](#): > > Quite, but the amateur fungus collector need only familiarise him or herself with a couple of dozen really good edible species and a handful of poisonous ones (especially those where there is any danger of confusion with the edible ones) - the rest can simply be treated as scenery. Indeed. But I wrote that because upon reading that the number of mushroom-related deaths (in \*\* chunkung \*\* link, for instance) is quite low, and then that there’s only a tiny number of deadly species, one could assume that the risk is extremely low, and that it’s quite safe to pick and eat some mushrooms, except if you’re extremely unlucky. So I wanted to clear things up by pointing out that the fact there are few deadly species doesn’t mean that these species are rare. If I were to spend an hour or two in the summer collecting mushrooms, picking indiscriminately all the fungi I find and eating them, the risk of ending up at the hospital would be close to 100% and the risk of ending up in a casket very significant. Of course, the number of lethal poisoning is quite low precisely because extremely few people would do such a thing. But one never knows. ---
**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, 9:53pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/28 "2004-04-25T21:53:17Z")
Thanks for that info; from the photo, I don’t think there’s any chance I’d mistke that for tricholoma gambosum, but certainly you can’t have too much information on a subject that involves life and death decisions, but a good book, intelligently read, can be quite adequate, as it should make mention of any possible misidentifications. Too much confidence is the killer and it is surprising how easy this is to come by for some people. ---
**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, 9:59pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/29 "2004-04-25T21:59:38Z")
> [@Mangetout](#): > > Even so, a spring-appearing fungus should be easy to ID. Probably the most popular spring mushroom where I live in the U.S. is the yellow morel (Morchella esculenta). It can, however, be confused with the poisonous false morel (Gyromitra esculenta) which also is a spring mushroom. This [page](http://www.bluewillowpages.com/mushroomexpert/morels/cardinal.html) gives some hints on how to distinguish the true from the false morel, but, I think I would advise anyone starting out to pick morels to listen to **clairobscur** and seek the assistance of an experienced (and cautious) collector. ---
**Author:** ![Tamerlane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tamerlane/32/7602_2.png) [@Tamerlane](https://boards.straightdope.com/u/Tamerlane)\ **Post date:** [April 25, 2004, 10:30pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/30 "2004-04-25T22:30:32Z")
> [@Mangetout](#): > > (\*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.) I’ll actually disagree with this, up to a point. In general, you’re right - the casual person probably doesn’t need to bother with taste. Any species you _need_ to taste to identify, almost certainly isn’t a good edible anyway. However there should be zero problem with any mushroom tasting, provided you do it properly ( tiny piece on tip of tongue, briefly nibbled, spit out with any associated saliva ). There are, I believe, a few genera ( I know at least _Russula_ falls into this category ) where at least a few species cannot be keyed out without tasting them. Again, not that this a burning issue for the casual nature-walker - it is more of interest to professional mycologists. But it really isn’t particularly dangerous. Besides you are depriving mycological pranksters of one of the great dirty tricks - getting a naive person to taste certain species of Russula to determine species and having them try one of the acrid ones, which is a bit akin to dipping your tongue in battery acid :D. Otherwise I agree with many of the above posts - don’t eat unless you are 100% sure of your ID ( and as with **clairobscur** there are a few I won’t eat even then, like Amanita calyptrata\*, aka coccoli, which in my neck of the woods are too close to Amanita phalloides\*, both in appearance and genetics, to be casual about ) and the only way to get 100% certain is be either a) somewhat experienced with that particular species or b) use a proper dichotomous key for that genus ( many of which require a good compound microscope ). There are NO shortcuts. Amanita phalloides is by all accounts delicious - but it will kill you deader than Dillinger. - Tamerlane ---
**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, 10:50pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/31 "2004-04-25T22:50:14Z")
> [@Danalan](#): > > 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? It’s always been my understanding that celery requires more calories to digest than it actually provides, hence a perfect diet food[except for its sodium content] ---
**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, 11:12pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/32 "2004-04-25T23:12:33Z")
> [@Tamerlane](#): > > I’ll actually disagree with this, up to a point. In general, you’re right - the casual person probably doesn’t need to bother with taste. Any species you _need_ to taste to identify, almost certainly isn’t a good edible anyway. However there should be zero problem with any mushroom tasting, provided you do it properly ( tiny piece on tip of tongue, briefly nibbled, spit out with any associated saliva ). There are, I believe, a few genera ( I know at least _Russula_ falls into this category ) where at least a few species cannot be keyed out without tasting them. Again, not that this a burning issue for the casual nature-walker - it is more of interest to professional mycologists. But it really isn’t particularly dangerous. I completely agree that it is safe if done properly and essential for mycologists, but for the gourmand it is superfluous - you’re either going to taste it at the table (where admittedly, cooking may have affected the taste), or you’ll have rejected it based on other attributes. And if young children were present, I wouldn’t ever do the taste test - some things that children _see_ are very difficult to _explain_ the importance or relevance of. When I go picking mushrooms for the table, there are perhaps a dozen or two dozen species that I’m actually looking for (and in most cases I’ll have to travel to their precise choice of habitat) and (primarily from half a dozen different books) I am not only very familiar with these species, but also aware of those which might be confused for something else (although some are absolutely unmistakeable) - I’ll often find many other species along the way that are _interesting_ and may actually be edible, but it doesn’t matter, because it is the Ceps, the Chantarelles, the Horse Mushrooms, the Giant Puffballs etc that I’m out to get - anything else is _scenery_, not food (although I might tentatively identify some of the scenery on my return home and come back another day to confirm). ---
**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, 11:41pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/33 "2004-04-25T23:41:08Z")
> [@chukhung](#): > > Is this advice intended for survival situations where it’s either eat something or die of starvation? Yes. :o Sorry I forgot to mention that. It also says to avoid bright colors and certain smells (such as almond) ---
**Author:** ![Tamerlane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tamerlane/32/7602_2.png) [@Tamerlane](https://boards.straightdope.com/u/Tamerlane)\ **Post date:** [April 25, 2004, 11:56pm UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/34 "2004-04-25T23:56:45Z")
> [@Dog80](#): > > Sorry I forgot to mention that. It also says to avoid bright colors and certain smells (such as almond) See, those don’t work for mushrooms either :). In plants the odor of almonds often = cyanide compounds. But several delicious ( edible ) species of Agaricus smell of almonds ( in this case deriving from benzyl aldehyde, rather than cyanide ) and some brightly colored mushrooms are decent edibles as well. - Tamerlane ---
**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 26, 2004, 12:02am UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/35 "2004-04-26T00:02:48Z")
> [@Tamerlane](#): > > some brightly colored mushrooms are decent edibles as well. > > - Tamerlane [Chanterelle](http://www.mit.edu/~jasonm/photos/Closeup/Chanterelle-S.jpg) (one of the most highly-prized wild fungi) [Amethyst Deceiver](http://home.freeuk.com/mistyvale/photo/gfx/pics/S/001/17/05.jpg) (I’ve eaten this one) ---
**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 26, 2004, 12:10am UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/36 "2004-04-26T00:10:55Z")
But as I said; in a survival situation, if there are fungi, there is probably decaying vegetation and if there is decaying vegetation, there are probably numerous highly-nutritious invertebrates to be found - OK, woodlouse soup it isn’t the nicest idea, but I’d rather eat that than risk a prolonged and painful death from organ failure or nerve destruction (two of the more common modes of fungus-related death). ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [April 26, 2004, 12:38am UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/37 "2004-04-26T00:38:54Z")
> [@Mangetout](#): > > the Giant Puffballs etc that I’m out to get - ). When I read the name “puffballs” I guessed what these could be, and a quick google search confirmed my guess (they’re called “wolf’s bladder”, over here). I looked at the pictures, and they’re impressive. The ones I know are small “puffballs”. And apart, as a child, stomping on them when they were mature for the pyrotechnic effect, I never had an interest in them. I had been told they were tasteless hence not worth picking. But since you seem to appreciate them, and given they’re quite common, perhaps I should investigate the matter. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [April 26, 2004, 12:42am UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/38 "2004-04-26T00:42:34Z")
Forget about it. My small “puffballs” are apparently only worth being stomped on… ☹ ---
**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 26, 2004, 12:50am UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/39 "2004-04-26T00:50:05Z")
Some of the smaller puffball species are edible and worthwhile (if picked when the flesh inside is still entirely white), but identification is actually quite tricky here and they aren’t anything like as impressive as the giant puffball (which, anecdotally, has been said to grow to such size that it has been mistaken, at a distance, for a sheep - the biggest one I’ve ever found was about football-sized). ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [April 26, 2004, 1:01am UTC](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925/40 "2004-04-26T01:01:25Z")
> [@Mangetout](#): > > [Chanterelle](http://www.mit.edu/~jasonm/photos/Closeup/Chanterelle-S.jpg) (one of the most highly-prized wild fungi) > [Amethyst Deceiver](http://home.freeuk.com/mistyvale/photo/gfx/pics/S/001/17/05.jpg) (I’ve eaten this one) There’s also this one : > **[California Fungi: Laccaria laccata](https://www.mykoweb.com/CAF/species/Laccaria_laccata.html)** > > Photographs and descriptions of the Mushrooms and other Fungi of California, USA Never eat it, but if I’m not mistaken about the specie, relatives of mine do. Lactarius also are brightly colored but I never collected them, either. And not all of them are edible. [Previous page](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925.md?page=1) [Next page](https://boards.straightdope.com/t/is-there-a-simple-test-to-determine-if-a-mushroom-is-eatable-or-poisonous/241925.md?page=3)