The Online Encyclopedia and Dictionary






Amanita muscaria

Amanita muscaria is a basidiomycete mushroom of the genus Amanita. A. muscaria var. muscaria, var. flavivolvata, and var. formosa are commonly called Fly Agaric (less often fly mushroom) or Toadstool.

Amanita muscaria growing in autumn
Amanita muscaria growing in
autumn Scottish woodland



Variety muscaria is a classic mushroom. Fully grown, the cap is usually around 12 cm in diameter (up to 30 cm) with a distinctive blood-red colour (crimson, fading to yellow with age), scattered with white to yellow, removable flecks (warts), which are remnants of the universal veil, a membrane that encloses the entire mushroom when it is still very young. The stem is white, 5-20 cm, with a basal bulb that bears universal veil remnants, in the form of a ragged collar or [group of] ruff[s] that circle[s] the base of the stalk (or stipe).

It grows on the ground in a number of different woodlands, although birch, pine, spruce and fir are common in its habitats. It is considered poisonous, though rarely fatally so. The name "Fly Agaric" comes from its European use as an insecticide: crushed, dipped, or sprinkled in milk. But it is sometimes consumed for its psychopharmacological effects. It is a very easily exported species that has been imported to many countries outside of Europe with, for example, pine plantations. When imported to a new country, muscaria can jump to native species (for example, Eucalyptus in Australia). It can then be exported with its new symbiont (for example, from Australia to Argentina).


Other varieties have similar appearance to var. muscaria, but differ most conspicuously in cap colour:

  • Var. alba is white and restricted to northern North America
  • Var. flavivolvata is red, with yellow warts, and has a range from southern Alaska to at least Andean Colombia
  • Var. formosa (poorly understood European var.) is orange-yellow.
  • Var. guessowii is yellow to orange, with center of cap more orange or reddish orange than the outer part, apparently restricted to northern North America
  • Var. persicina is pinkish to orangish "melon" colored with poorly formed or absent remnants of universal veil on the stem and vasal bulb
  • Var. regalis is liver-brown and has yellow warts (now treated as a separate species (A. regalis).

Toxicity and chemistry

It contains a number of entheogenic constituents: ibotenic acid, muscimol, muscazone and muscarine, of which muscimol (3hydroxy-5-aminomethy-1 isoxazole, an unsaturated cyclic hydroxamic acid ) is the most significant. Muscarine, discovered in 1869, was long thought to be the hallucinogenic chemical until late 1960s, when scientists recognized it as ibotenic acid and muscimol.

Consuming the mushrooms in doses of over 1 gram can cause nausea but also can cause a number of other effects, depending on dosage, ranging from twitching to drowsiness, cholinergic effects (lower blood pressure, increase sweat and saliva), visual distortions, mood changes, euphoria, relaxation, and hallucinations. In near fatal doses it causes swollen features, high rage and madness, characterised by bouts of mania, followed by periods of quiet hallucination. Effects appear after 60 minutes or so, peak within three hours, but certain effects can last for up to ten hours. The effect per volume consumed is highly variable and individuals can react quite differently to the same dose. The mushroom has been mistaken for other yellow to red species in the Americas (for example, Armillaria cf. mella and the edible Mexican species Amanita basii (similar to A. caesarea of Europe)). Poison control centers in the U.S. and Canada are aware that amarillo is a common name of caesarea-like species in Mexico, not just the Spanish for 'yellow'.

Deaths from A. muscaria are extremely rare. Fatal doses have occurred in North America (var. guessowii). The amount and ratio of chemical compounds per mushroom varies widely from region to region, season to season, further confusing the issue. Many older books list it as deadly, giving the impression that it is far more toxic than it really is. The vast majority of mushroom poisoning fatalities (90+ %) are from having eaten either the greenish to yellowish to brownish mottled Death Cap (Amanita phalloides) or one of the Destroying Angels (Amanita virosa), several overall white Amanita species.


This mushroom, like its psychoactive relatives the Psilocybe species, have been used in rituals to communicate to the spirit world, largely in Siberia, with small reported incidents elsewhere in the northern hemisphere. Mesoamericans never consumed fly agaric for religion, but instead use Psilocybe.

The active ingredient is excreted in the urine of those consuming the mushrooms, and it has sometimes been the practice for a shaman to consume the mushrooms, and the rest of the tribe to drink his urine: the shaman, in effect, partially detoxifying the drug (the sweat- and twitch-causing muscarine is absent in the urine). If a fly agaric is eaten, it is usually not fresh, but in its sun-dried form, where the hallucinogenic chemicals are more concentrated (ibotenic acid converted to the more stable muscimol).

It has been suggested that the berserkers took the fly agaric before battle.

  • [1] Fly Agaric, Father Christmas and Lunch with a Toxicologist Article

Mythology and religion

Koryak Siberians have a story about the fly agaric (wapaq) which enabled Big Raven to carry a whale to its home. In the story, the deity Vahiyinin ("Existence") spat onto earth, and his spittle became the wapaq, and his saliva becomes the warts. After experiencing the power of the wapaq, Raven was so exhilarated that he told it to grow forever on earth so his children, the people, can learn from it.

Amanita muscaria is widely thought to be the Soma talked about in the Hindu scriptures, and is less often also thought to be the amrita talked about in Buddhist scriptures.

Garden ornaments, and children's picture books depicting gnomes and fairies very often show fly agaric mushrooms used as seats, or homes; it is rather uncommon for any other mushroom to be shown in this role. How this artistic convention arose is a matter of speculation.

External links

Fly Agaric, Father Christmas and Lunch with a Toxicologist - article [2]

Last updated: 08-15-2005 12:01:07
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