Amanita muscaria

• 1. Introduction

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  Amanita muscaria has been killing flies, inspiring myths, and bewildering scientists for centuries. The mushroom most people picture when they imagine a toadstool is this one: a bright red cap fringed with white warts, growing at the foot of a birch or pine. Its image has appeared in Hieronymus Bosch paintings, Disney films, and Mario video games. Yet behind that familiar silhouette lies a genuinely strange organism whose chemistry, ecology, and cultural history are far more complicated than a garden gnome suggests.

  Who named it, and why? What does it actually do to the brain? Did Viking warriors really take it before battle? Did the Rigveda's sacred soma drink come from this forest mushroom? And why, in 2024, did Google searches for it nearly double in a single year? Those are the questions this documentary will answer.

• 2. A Name Born From Flies

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  Albertus Magnus was the first writer to set down the mushroom's insect-killing reputation in his work De vegetabilibus, completed before 1256, where he called it the fly mushroom because it was "powdered in milk to kill flies." The practice he described was widespread. It has been recorded from Germanic- and Slavic-speaking regions of Europe, from the Vosges region of France, from pockets elsewhere in France, and from Romania.

  The 16th-century Flemish botanist Carolus Clusius traced the fly-killing tradition to Frankfurt in Germany. Carl Linnaeus, the man known as the father of taxonomy, reported the same custom from Småland in southern Sweden, the region where he spent part of his childhood. In 1753 Linnaeus formally described the fungus in volume two of his Species Plantarum, giving it the name Agaricus muscarius, drawing the specific epithet from the Latin musca, meaning fly.

  In 1783, the French naturalist Jean-Baptiste Lamarck moved it into the genus Amanita. That name was then sanctioned in 1821 by the Swedish mycologist Elias Magnus Fries, often called the father of mycology. A series of rule changes to the International Code of Botanical Nomenclature in 1987 reset the valid starting date for fungal names to the 1st of May 1753, so Linnaeus and Lamarck are now jointly credited as namers of Amanita muscaria.

  Not everyone was convinced the fly-killing story was the true origin. The English mycologist John Ramsbottom noted that "bug agaric" was an old alternative name for the species. The French mycologist Pierre Bulliard tried and failed to replicate the fly-killing properties and proposed a different binomial altogether in his 1784 book. One compound since isolated from the fungus is 1,3-diolein, a substance that does attract insects; some researchers have speculated that flies seek out the mushroom deliberately for its intoxicating effects. An alternative folk etymology links "fly" not to insects at all but to the medieval belief that flies could enter a person's head and cause madness. Regional names support this reading: oriol foll in Catalan, tsapi de diablhou ("Devil's hat") in a local dialect of Fribourg in Switzerland.

• 3. Inside the Chemistry

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  Muscarine was discovered in 1869 and for a long time researchers assumed it was the compound responsible for the mushroom's hallucinogenic effects. That assumption turned out to be wrong. The levels of muscarine in A. muscaria are far lower than in other toxic fungi such as Inosperma erubescens, and they are too low to account for the poisoning symptoms the mushroom actually produces.

  Researchers working in England, Japan, and Switzerland eventually identified the real agents: muscimol and ibotenic acid, both discovered in the mid-20th century. Ibotenic acid is a neurotoxin that acts as a prodrug; drying the mushroom converts ibotenic acid into the more potent muscimol. Muscimol is a potent agonist of GABAA receptors, structurally related to the inhibitory neurotransmitter GABA. Ibotenic acid, meanwhile, acts as an agonist of NMDA glutamate receptors and certain metabotropic glutamate receptors involved in controlling neuronal activity. An active dose in adults is approximately 6 mg of muscimol or 30 to 60 mg of ibotenic acid, typically about the amount found in a single cap.

  The compounds are not distributed evenly through the mushroom. Most are concentrated in the cap; a moderate amount sits in the base; the stalk carries the smallest quantity. Spring and summer specimens have been reported to contain up to ten times more ibotenic acid and muscimol than mushrooms fruiting in autumn.

  Between 20 and 90 minutes after ingestion, a substantial fraction of ibotenic acid is excreted unmetabolised in the urine. This pharmacological fact underpins the documented Siberian practice of drinking the urine of someone who had already consumed the mushroom: the initial consumer appears to filter out many of the compounds responsible for unpleasant side effects such as sweating and twitching, so the secondary drinker receives a purer muscimol load. A further compound, muscazone, has been isolated from European specimens; it forms when ibotenic acid breaks down under ultraviolet radiation, but it has minor pharmacological activity compared with the other agents. The mushroom also bioaccumulates vanadium at concentrations up to 400 times those typically found in plants, held in a compound called amavadine, though the biological significance of this accumulation remains unknown.

• 4. What Poisoning Looks Like

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  Symptoms typically appear 30 to 90 minutes after eating and peak within three hours. The range of effects is wide: mild cases bring nausea, twitching, and drowsiness; more intense doses can produce auditory and visual distortions, mood changes, euphoria, ataxia, and loss of equilibrium. In serious cases the mushroom causes delirium characterised by bouts of marked agitation, confusion, hallucinations, and irritability, followed by periods of central nervous system depression. Seizures and coma may occur in the most severe poisonings.

  Most people recover fully within 12 to 24 hours. Some suffer headaches for up to ten hours after the main episode; retrograde amnesia and lingering drowsiness have also been reported. Deaths from A. muscaria poisoning have appeared in historical journal articles and newspaper reports, but the North American Mycological Association has stated that there were "no reliably documented cases of death from toxins in these mushrooms in the past 100 years." The author and mycologist David Arora has argued that the widespread listing of A. muscaria as deadly in field guides is an error that overstates the mushroom's actual toxicity.

  There is no antidote. Treatment focuses on supportive care. If a patient arrives within four hours of ingestion, activated charcoal is given; gastric lavage is considered within the first hour. Despite the fact that muscarine was originally isolated from A. muscaria and gives the muscarinic receptor its name, muscimol does not act on muscarinic acetylcholine receptors, meaning atropine and physostigmine are not appropriate as antidotes. Benzodiazepines such as diazepam or lorazepam can be used for agitation, though only in small doses to avoid compounding muscimol's respiratory depressant effects. In the most serious cases, intubation and artificial ventilation may be needed, and hemodialysis can remove the toxins, though that intervention is generally considered unnecessary. With modern medical care, the prognosis is typically good.

• 5. Siberian Shamans and Disputed Origins

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  Indigenous peoples of Siberia used A. muscaria as an inebriant and an entheogen in what accounts describe as a non-sacred, non-obligatory, and often recreational way. The Koryak of eastern Siberia preserved a myth about the mushroom, which they called wapaq, in which the deity Vahiyinin spat onto the earth and his spittle became the wapaq, his saliva forming the white warts. Big Raven, having experienced the power of the wapaq, commanded it to grow on earth forever so that people could learn from it. Among the Koryak, one report recorded that poorer community members would drink the urine of wealthier individuals who could afford to buy the mushrooms. Reindeer were reportedly drawn to the urine of intoxicated people and became similarly intoxicated themselves; the Koryak reportedly used the drunken state of the reindeer to rope and hunt them more easily.

  In Lithuania, ethnographer Marija Gimbutas reported to the mycologist R. Gordon Wasson that A. muscaria had been consumed at wedding feasts mixed with vodka in remote areas, and that Lithuanians once exported the mushroom to the Sami in the far north for shamanic rituals.

  Those Siberian connections fed a series of sweeping and contested theories. In 1968, Wasson proposed that A. muscaria was the soma described in the Rigveda, noting that descriptions of soma mentioned no roots, stems, or seeds, that the adjective hári suggesting redness was applied to it, and that one line depicted men urinating soma. Vedic scholar John Brough from Cambridge University rejected the theory in 1971, arguing the language was too vague to identify any specific substance. There is now established scholarly consensus that the botanical identity of soma is Ephedra, particularly Ephedra gerardiana, Ephedra intermedia, or Ephedra equisetina.

  The Viking berserker theory has a similarly thin foundation. The Swedish professor Samuel Ödmann first proposed in 1784 that Norse warriors consumed A. muscaria to produce their berserker rages, basing his idea on Siberian shamanic reports. No contemporary sources mention this use in descriptions of berserkers, and comparative analysis of symptoms has since suggested Hyoscyamus niger as a better match for the berserker state than muscimol, which is generally a mild relaxant.

  In 1970, philologist and Dead Sea Scrolls scholar John Marco Allegro argued in The Sacred Mushroom and the Cross that early Christian theology derived from a fertility cult centred on the entheogenic consumption of A. muscaria. The book drew sharp criticism from academics including Sir Godfrey Driver, emeritus Professor of Semitic Philology at Oxford University, and Henry Chadwick, Dean of Christ Church, Oxford. John C. King's rebuttal pointed out that fly agarics and their host trees are not found in the Middle East, and that if the theory were correct the mushroom's use would have to have been "the best kept secret in the world" for two thousand years. That theory also found little scholarly support beyond the field of ethnomycology.

• 6. Distribution and Ecology

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  A. muscaria is native to conifer and deciduous woodlands across the temperate and boreal regions of the Northern Hemisphere, from higher elevations in the Hindu Kush and Central America to the forests of Alaska. A molecular study has proposed that it originated in the Siberian-Beringian region during the Tertiary period and spread outward across Asia, Europe, and North America from there. Specimens from three distinct genetic clades have all been found in Alaska, supporting the hypothesis that Alaska was the centre of diversification.

  A 2006 molecular phylogenetic study by mycologist Jozsef Geml and colleagues identified three major clades: roughly Eurasian, Eurasian subalpine, and North American populations. A follow-up study published in 2008 found those three groups, plus a fourth associated with oak-hickory-pine forest in the southeastern United States and two more populations on Santa Cruz Island, California, to be genetically distinct enough to constitute separate species. This means A. muscaria as currently understood is a species complex.

  Conveyed with pine seedlings, the mushroom has spread widely into the Southern Hemisphere. It is now found in Australia, New Zealand, South Africa, and several Brazilian states including Parana, Sao Paulo, Minas Gerais, and Rio Grande do Sul. In New Zealand, Tasmania, and the Australian state of Victoria it behaves like a weed, forming new associations with southern beech. In 2010 it was recorded under silver birch in Manjimup, Western Australia. It has since been found near Port Macquarie on the New South Wales north coast, and appears to be spreading northward. One rainforest in Australia is now being invaded by the species, raising concerns that it may displace native fungi.

• 7. Edible, Iconic, and Increasingly Regulated

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  Georg Heinrich von Langsdorff, a German physician and naturalist, published the first known account of how to detoxify A. muscaria in 1823. Parboiling and discarding the cooking water removes most of the water-soluble toxins. In the late 19th century the French physician Felix Archimede Pouchet advocated for eating the mushroom after detoxification, comparing it to manioc, a tropical food staple that must also be rendered safe before consumption. American botanist Frederick Vernon Coville recorded a classic description of an African-American mushroom seller in Washington, D.C., who prepared it by parboiling and soaking in vinegar to make a sauce for steak. In Nagano Prefecture in Japan the most well-known current use is salting and pickling. A 2008 paper by food historian William Rubel and mycologist David Arora argued that the widespread labelling of the mushroom as poisonous in field guides reflects cultural bias, since morels and other popular edible species are also toxic unless properly cooked.

  In popular culture the mushroom's image is everywhere. Hieronymus Bosch placed one on the left-hand panel of The Garden of Earthly Delights. The dancing mushroom sequence in the 1940 Disney film Fantasia drew on its silhouette. The Mario franchise incorporated two Super Mushroom power-up items and fly-agaric-shaped platforms into several stages. Naturalist Mordecai Cubitt Cooke described the size distortions caused by the mushroom's effects in his books, observations that are thought to have influenced the 1865 story Alice's Adventures in Wonderland. Thomas Pynchon's 1973 novel Gravity's Rainbow gives a detailed account of a character preparing a cookie bake mixture from harvested A. muscaria. Alan Garner's 2003 novel Thursbitch explores fly agaric shamanism in the context of a surviving Dionysian cult in the Peak District.

  In 2024, Google searches for Amanita muscaria rose nearly 200 percent from the previous year. An article in the American Journal of Preventive Medicine linked that spike to the sudden commercialisation of A. muscaria products online. In December 2024 the FDA banned A. muscaria extracts from food products following an outbreak of poisonings and at least one death associated with those products. A month into 2025, Germany's Federal Institute for Risk Assessment warned that muscimol-containing products shaped like sweets had reached the market and posed serious risks, particularly to children. The mushroom that Albertus Magnus described killing flies in milk before 1256 is now under the scrutiny of the United States Food and Drug Administration.