(Montpelier, VT, USA)
...If you eat them raw. NEVER eat any edible wild mushrooms raw. Always thoroughly cook them.
Some mushrooms, even good edibles, contain elements that can cause stomach upset. Cooking wild mushrooms essentially stabilizes (or chemically changes?) the components that could cause gastric discomfort.
In the early 1960s, my father, using a European mushroom guide, picked and ate some green russula fungi raw, on a salad. He became extremely ill for hours, and was taken to the emergency room where they administered an antidote. He recovered, but for years he avoided wild mushrooms.
His experience points up another proviso: Make sure you have a fairly recent, North American mushroom guide that has clear, detailed photographs. Mushrooms in foreign guidebooks may look the same as American species, but they may be different than those you find here, and possibly inedible or poisonous. Several national and regional mushroom societies are online, so check those sites for recommended field guides. Avoid coffee table books not only due to size, but they're also not necessarily intended as identification guides.
Other things to remember:
- Sometimes some individuals are allergic to perfectly edible wild mushrooms. One person I know of discovered that he is allergic to chanterelles, even though that species is not known to cause any discomfort when consumed. (Exactly the opposite, in fact.)
- On the other hand, there are a few edible mushrooms are known to cause discomfort in some people, even though most people enjoy them without any difficulty. One example is the Honey mushrooms (Armillaria mellea).
- For that reason, when trying a new wild fungus for the first time, only eat a small portion. That way you can see if you have an allergic reaction.
- Another factor to keep in mind is that some mushrooms don't mix well with alcohol consumption. One particular fungus that requires complete avoidance of alcohol is the Shaggy Mane (Coprinus comatus). The risk of stomach upset even lasts for some time after consuming the mushrooms.
With these provisos and a good mushroom expert to confirm your findings - enjoy! Wild mushrooms can provide culinary delights beyond your expectations.