Amanita Muscaria - Toxicity

Toxicity

Amanita muscaria poisoning occurs in either young children or people ingesting it to have a hallucinogenic experience. Occasionally, immature button forms have been mistaken for puffballs. Additionally, the white spots can be washed away during heavy rain and it then may seem as the edible A. caesarea.

Amanita muscaria contains a number of biologically active agents, at least one of which, muscimol, is known to be psychoactive. Ibotenic acid, a neurotoxin, serves as a prodrug to muscimol, with approximately 10-20% converting to muscimol upon ingestion. A toxic dose in adults is approximately 6 mg muscimol or 30 to 60 mg ibotenic acid; this is typically about the amount found in one cap of Amanita muscaria. However, the amount and ratio of chemical compounds per mushroom varies widely from region to region and season to season, which further confuses the issue. Spring and summer mushrooms have been reported to contain up to 10 times as much ibotenic acid and muscimol compared to autumn fruitings.

A fatal dose has been calculated at an amount of 15 caps. Deaths from this fungus A. muscaria have been reported in historical journal articles and newspaper reports; however, with modern medical treatment a fatal outcome because of the poison of this mushroom would be extremely rare. Many older books list it as "deadly" but this is a mistake that gives the impression it is far more toxic than it actually is. The North American Mycological Association has stated there are absolutely no reliably documented fatalities in the past century. The vast majority (90% or more) of mushroom poisoning deaths are from having eaten either the greenish to yellowish death cap (A. phalloides) or perhaps even one of the several white Amanita species which are known as destroying angels.

The active constituents of this species are water soluble, and boiling and then discarding the cooking water will at least partly detoxify A. muscaria. However, drying may increase potency as the process facilitates the conversion of ibotenic acid to the more potent muscimol. According to some sources, once detoxified, the mushroom becomes edible.