mushroom poisoning, fungal poisoning caused by ingestion of certain mushrooms (fungal organisms), most commonly Amanita phalloides and Amanita muscaria and related species. Symptoms, caused by toxic peptides, may include severe abdominal pain, vomiting, cold sweat, diarrhea, and excessive thirst; they appear 8 to 12 hours after ingestion. Damage occurs largely in the liver and kidneys. Some mushrooms contain substances that produce hallucinatory states, e.g., Psilocybe mexicana (see hallucinogenic drug; ergot). Occasional outbreaks of poisoning from eating canned mushrooms are not caused by poisonous mushrooms but by botulism resulting from improper canning methods.

mushroom, type of basidium fungus characterized by spore-bearing gills on the underside of the umbrella- or cone-shaped cap. The name toadstool is popularly reserved for inedible or poisonous mushrooms, but this classification has no scientific basis. The only safe way of distinguishing between the edible and the poisonous species is to learn to identify them. Some poisonous mushrooms are of the genus Amanita. The genus includes the fly agaric, Amanita muscaria, and the death angel or destroying angel, A. virosa.

The use of edible mushrooms for food dates back at least to early Roman times. Originally a delicacy for the elite, mushrooms are now extensively grown on a commercial scale, especially the cultivated mushroom or champignon, Agaricus bisporus, and the shiitake mushroom, Lentinus edodes. Their culture requires careful control of temperature and humidity. The bulk of the crop in the United States is grown near Philadelphia. In Europe more than 50 species of mushrooms are marketed. Although mushrooms contain some protein and minerals, they are largely composed of water and hence are of limited nutritive value.

The truffle, puffball, and other edible fungi are sometimes also called mushrooms. In all cases the term mushroom is properly restricted to the above-ground portion, which is the reproductive organ. Mushrooms are classified in the kingdom Fungi, phylum (division) Basidiomycota.

or toadstool poisoning

Sometimes fatal effect of eating any of the 70–80 species of poisonous mushrooms, or toadstools. Many contain toxic alkaloids. The most deadly, Amanita phalloides (“death cup”), causes violent abdominal pain, vomiting, and bloody diarrhea. Severe liver, kidney, and central-nervous-system damage lead to coma. Over half the victims die. Treatment with thioctic acid, glucose, and penicillin or by filtering the blood with charcoal may be effective. A. muscaria causes vomiting, diarrhea, excessive perspiration, and confusion, with recovery within 24 hours. Gyromitra esculenta toxin is usually destroyed by cooking, but in susceptible people it affects the central nervous system and breaks down blood cells, causing jaundice. Some poisonous mushrooms resemble harmless ones, so extreme caution is needed in wild-mushroom gathering.

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Fleshy spore-bearing structure of certain fungi (see fungus), typically of the phylum Basidiomycota. It arises from the mycelium, which may live hundreds of years or a few months, depending on its food supply. Some species grow cellular strands (hyphae) in all directions, forming a circular mat with a “fairy ring” of fruiting bodies around the outside. Popularly, “mushroom” refers to the edible sporophores, while “toadstool” refers to inedible or poisonous sporophores, but there is no scientific distinction between the two names. Umbrella-shaped sporophores with spore-shedding gills on the undersurface are found chiefly in the agaric family (Agaricaceae). Mushrooms that are cap-shaped and bear spores in an easily detachable layer on the underside of the cap belong to the family Boletaceae. Together the agarics and boletes include most of the forms known as mushrooms. The morels (phylum Ascomycota) are popularly included with the true mushrooms because of their shape and fleshy structure. Since some poisonous mushrooms closely resemble edible ones, mushrooms intended for eating must be accurately identified. Mushroom poisoning can cause nausea, diarrhea, vomiting, cramps, hallucinations, coma, and sometimes death.

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