Toxic Mushrooms
Some varieties of mushrooms are poisonous (toxic) and can cause illness and even death if they are eaten. The toxins involved in mushroom poisoning are produced naturally by the fungi themselves; each individual specimen of a toxic species should be considered equally poisonous. Most mushrooms that cause human poisoning cannot be made nontoxic by cooking, canning, freezing or any other means of processing. Thus, the only way to avoid poisoning is not to eat the toxic species.
Mushroom poisonings in the United States occur most commonly when hunters of wild mushrooms (especially novices) misidentify and consume a toxic species; when recent immigrants collect and consume a poisonous American species that closely resembles an edible wild mushroom from their native land; or when mushrooms that contain psychoactive compounds are intentionally consumed by people who desire these effects.
Mushroom poisonings are generally acute and cause a variety of symptoms and outcomes, depending on the amount and species consumed. Because the chemistry of many of the mushroom toxins (especially the less deadly ones) is still unknown and positive identification of the mushrooms is often difficult or impossible, mushroom poisonings are generally categorized by their physiological effects. There are four categories of mushroom toxins: protoplasmic poisons (poisons that result in generalized destruction of cells, followed by organ failure and death); neurotoxins (compounds that cause neurological symptoms such as profuse sweating, coma, convulsions, hallucinations, excitement, depression, spastic colon); gastrointestinal irritants (compounds that produce rapid, transient nausea, vomiting, abdominal cramping, and diarrhea); and disulfiram-like toxins. Mushrooms in this last category are generally nontoxic and produce no symptoms unless alcohol is consumed within 72 hours after eating them, in which case a short-lived acute toxic syndrome is produced.