Some wild species are toxic, or at least indigestible, when raw. Failure to identify poisonous mushrooms and confusing them with edible ones has resulted in death. Some
mobile applications exist to aid with identification, but are unreliable on their own, especially those based on
artificial intelligence. Deadly poisonous mushrooms that are frequently confused with edible mushrooms and responsible for many fatal poisonings include several species of the genus
Amanita, particularly
A. phalloides (the death cap). Some mushrooms that are edible for most people can cause
allergic reactions in some individuals with no prior knowledge of an allergy; old or improperly stored specimens can go rancid quickly and cause
food poisoning. When eating any fungus for the first time, only a small quantity of one species should be consumed at a time, allowing for several hours to identify any potential allergic reaction. Even normally edible species of mushrooms may be dangerous, as certain mushrooms growing in polluted locations can act as chemical-absorbers,
accumulating pollutants and
heavy metals, including
arsenic and
iron, sometimes in lethal concentrations. On the other hand, cooking preparations may reduce the toxicity of certain slightly poisonous mushrooms (e.g. Morchellas) enough to be consumed. Additionally, several varieties of fungi are known and documented to contain
psychedelic drugs—the so-called
magic mushrooms—yet resemble perfectly edible, non-
psychoactive species. While not necessarily lethal to consume, to the uninitiated, an accidentally induced psychedelic experience can run the gamut from benign to terrifying, even depressing or psychotic. The most commonly consumed for recreational psychoactive use are
Amanita muscaria (the fly agaric) and
Psilocybe cubensis, with the former containing alkaloids such as
muscimol and the latter predominately
psilocybin. Both have the potential to induce in the user feelings of awe, wonder with nature, interesting visual hallucinations and inner peace (even in mild doses), but excessive or accidental consumption can create feelings of insanity, helplessness and fear, usually persisting for a few hours. ==Nutrition==