# Fly agaric (Amanita muscaria)

**Amanita muscaria**

**Known today as.** The red, white-spotted toadstool of fairy tales, of birch and pine woods.

Kind: Fungus  
Poisoning: Ibotenic acid and muscimol (pantherine syndrome) (https://thethinkingpress.org/materia-medica/poisons/pantherine)  
Toxic: yes

> **Caution.** Poisonous.

## What was it used for?

Powdered in milk to kill flies, as Albertus Magnus recorded in the thirteenth century; eaten as an intoxicant by peoples of Siberia.

## What does modern science say?

Its ibotenic acid and muscimol cause delirium, drowsiness, and vivid dreams. Deaths are rare, but it is a poison. Muscimol, its chief drug, acts on the brain’s GABA receptors like a strong sedative, and ibotenic acid, which becomes muscimol on drying, is a nerve excitant; together they bring drowsiness, twitching, confusion, and sometimes vivid dreams, usually ending in recovery within a day. Muscarine, named from it, is present only in traces.

## Pharmacognosy and toxicology

- **ibotenic acid**: 
- **muscimol**: formed from ibotenic acid on drying
- **muscarine**: traces only

**Mechanism.** Muscimol is a GABA-A agonist; ibotenic acid a glutamate agonist.

**Dose.** The effect varies widely, and similar doses can act quite differently in different people; with modern treatment, deaths are extremely rare.

**Standing.** None; after an outbreak of poisonings from products containing it, the US Food and Drug Administration banned its use in food in December 2024.

## What lore surrounds it?

The toadstool of fairy tales and children’s books. Among the Koryak and other Siberian peoples it was taken by shamans and others, and its effects were said to pass into the urine of those who ate it. R. Gordon Wasson argued in 1968 that it was the Soma of the Rigveda.

Travellers’ reports of how it distorts the size of things are thought to lie behind the mushroom Alice eats in *Alice’s Adventures in Wonderland* (1865). Wasson’s identification of it with Soma is now doubted, and the theory that berserkers ate it before battle has no ancient source. Santa Claus’s flying reindeer have been read as a memory of its use by S mi shamans, a reading the S mi themselves reject.

## What did the older authorities say?

**Albertus Magnus.** Recorded, some time before 1256, that it was called the fly fungus because, powdered in milk, it kills flies; its name in many European languages is thought to come from this use.

**The Koryak and Chukchi.** Dried it in the sun or over the hearth and ate it, and many shamans took it before their seances, as Waldemar Jochelson recorded of the Koryak; the Chukchi tore it into pieces and chewed it. Those who could not afford it drank the urine of those who had eaten it and became as drunk, and Georg Steller wrote that when the Koryak met a reindeer intoxicated by the mushroom they tied its legs until the effect had passed.

**Linnaeus.** Named it *Agaricus muscarius* in 1753; Lamarck moved it to *Amanita* in 1783.

## Sources

- Albertus Magnus, *De vegetabilibus*.
- Wasson, R. G. (1968). *Soma: Divine Mushroom of Immortality*.
- Michelot, D., and Melendez-Howell, L. M. (2003). “*Amanita muscaria*: chemistry, biology, toxicology, and ethnomycology.” *Mycological Research* 107.
- Wikipedia contributors. “Amanita muscaria.” *Wikipedia, The Free Encyclopedia*. en.wikipedia.org/wiki/Amanita_muscaria (read 2 October 2026).
- Wikipedia contributors. “Muscimol.” *Wikipedia, The Free Encyclopedia*. en.wikipedia.org/wiki/Muscimol (read 2 October 2026).
- Wikipedia contributors. “Ibotenic acid.” *Wikipedia, The Free Encyclopedia*. en.wikipedia.org/wiki/Ibotenic_acid (read 2 October 2026).
- Michelot, D., and Melendez-Howell, L. M. (2003). *Mycological Research* 107.

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*Fly agaric.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-03. The Thinking Press. https://thethinkingpress.org/materia-medica/fly-agaric

Historical description, not medical advice.