Amanita virosa; The deadliest mushroom in Maine

Scope of the Problem: Mushroom Poisoning in the US

How Often are People Poisoned:

The perception of poisoning by wild mushrooms among the general public is often starkly in contrast with available facts.  I commonly speak with people who state they know of someone, or often a whole family, who died following a meal of wild mushrooms.  Statistics on mushroom poisoning in the US are kept in a variety of fashions and by a number of players.  Most easily available are reports from the network of poison centers located across the US.  They track contacts made to centers related to exposure to mushrooms as well as those cases that actually produce symptoms.  Some reports of mushroom poisoning confuse exposure with poisoning.  This can be highly misleading; in a review of mushroom poisoning records in California covering 5 years, 6,300 exposures were reported and more than 4200 were in children where only 6% developed symptoms of poisoning.  In total, less than half of the exposure patients developed symptoms, 0.3% showed “Major effects” and 1% were admitted to a critical care unit.  During this 5 year period(1993-97), there was one death reported in California.

The incidence of mushroom poisoning and the rate of serious injury and death in the United States seems to be increasing in direct proportion to the rapid rise in people foraging for wild mushrooms.  No surprise there….  Over the past 35 years an average of 2-3 people per year die of


The deadly Destroying Angel

mushroom poisoning in the US, according to the toxicology report of the North American Mycological Association (NAMA) with recent years on the high side.  As more Americans begin to collect mushrooms for food, we can expect numbers to rise and may begin to approach the much higher rates in most European countries.  Since 1982, NAMA has collected mushroom poisoning data using its National Mushroom Poisoning Case Registry and it does appear that we are experiencing an increase in poisoning cases. Still, if you compare that with lightning strikes as a cause of death, you may never venture out into the rain. The National Weather Service reports an average of 58 deaths per year from lightning between 1979-2008.


Who is most at Risk

To put it tritely, you will never be poisoned by a mushroom you do not eat.  On the other hand, not eating wild mushrooms deprives you of the experience of eating some fantastic meals.  Is there a group of (mushroom eating) people that are at increased risk of being poisoned by wild mushrooms?  Yes, and they fit several different categories.

Mycophageous Stranger in a Strange Land:  A significant proportion of the people suffering significant poisoning from mushrooms are


Though known as an edible in parts of the US, the Lilac Brown Bolete has seriously sickened many people in New England

visitors or recent immigrants from another country who eat a toxic mushroom that resembles an edible type back home.  This is especially dangerous fro those folks who eat Death Caps (Amanita phalloides) thinking they are an edible Volvariella.  I have also seen this in Europeans eating Lilac Brown Boletes, or other toxic boletes in Maine and believing they were an edible Bolete known from Germany.     It is vital that a newcomer learn the regional mushrooms before venturing forth to collect for dinner; a local guide is helpful.  Look here for more information on the Lilac Brown Bolete.

 The Grazer:  As mentioned above. a significant majority of mushroom exposures that result in calls to Poison centers, Emergency Departments or others, are the result of small children found in the possession of a wild mushroom, or with one in their mouth or, worst of all, holding a mushroom with a bite already out of the cap.  Most kids are under age 6 and the vast majority never show symptoms of having been poisoned.  Prudence is wise, however. since young children are more vulnerable to toxins because of their immature digestive and immune systems.

The Magical Thinker Each season a number of calls come in from adults who are sickened after having eaten a mushroom based on its benign appearance.   I shudder at the very thought, though I have handled several such calls.  “I just knew it couldn’t be bad because it looked so good”.   Never eat a mushroom unless you are certain of the identity and of its edibility.  When in doubt, don’t!.

Mistaken identity and other pitfalls:  Finally, a large number of poisonings occur when a forager makes a mistake.  The mistake might


This toxic Chanterelle Look-alike causes severe GI distress

take one of several forms:

  • A mistaken identification based on hasty or sloppy work, or inadequate knowledge and resources.  Mistaken ID only becomes a problem if the mushrooms are eaten. Every year people mistake the toxic Jack O;lantern for an edible Chanterelle.
  • Eating mushroom that were too old and spoiled, or contaminated by psticides or other toxins.
  • Eating a mushroom that does not agree with you or for which you have an allergic reaction.  Sometimes this is called idiosyncratic.  For example, some people cannot tolerate Honey mushrooms (Armillaria spp.) or the Chicken of the Woods (Laetiporus).
  • Overindulgence or inadequate cooking is sometimes responsible for sickenings.


Mushroom Toxins

Poisonous mushrooms and their toxins are grouped together by their mode of action on the body.  For some, this is related to a specific chemical compound or a class of related compounds.  For others, such as the gastrointestinal irritants, there may be many different compounds that produce similar unpleasant symptoms.  Depending on which system you follow and how detailed you wish to get, there are between 7 and 14 groups of toxins or syndromes of symptoms.  I will list the more significant or problematic types for the Northeast US.


The Problematic Few Toxin Groups (East Coast Version)

Amatoxins: The worst of the worst: Across the world 80-90% of deaths and severe mushroom poisonings are attributed to the group of mushroom that contain these cyclic peptides that cause damage by inhibiting the cells ability to make protein.  The result is damage to or failure of the liver and it quickly becomes life threatening.  There is a 50% fatality rate for people poisoned unless they live in an area with prompt, informed,  state of the art treatment.  Even then, the fatality rate remains at 10%.  Onset of symptoms is delayed 6-12 hours after eating and the initial phase is severe GI distress followed by a second latent period before the symptoms of acute liver failure show.

Found in several common species of Amanita,  including The Destroying Angels, A. virosa & bisporigera, The Death Cap, A. phalloides and several other species.  The toxins also occur in several small members of the genera Lepiota and Galerina, as well as Conocybe.   The majority of poisonings are attributed to Amanitas with the Death Cap being most dangerous and the most frequent cause os severe illness and death.  Fortunately it is quite rare in Northern New England, though becoming fairly common in parts of New York, New Jersey and Connecticut.  It is very important that a mushroomer learn to identify the Amanitas and become familiar with the features of the Galerina and Lepiota mushrooms.

Gyromitrin (Monomethylhydrazine): Mushrooms that contain gyromitrin can cause severe illness, liver damage and have caused a


An spring mushroom common in Pine forest, False morels are very toxic!

number of deaths over the past century, mostly in Europe.   The False morels contain the toxins as well as other genera.  The toxin is highly volatile and those people with a history of eating false morels without problems have learned to safely prepare them.   This involves boiling them in lots of water at least twice, though even fully cooked mushroom have been shown to contain Gyromitrin.  An additional risk is posed by breathing in the fumes generated in the boilinh provess.    Once poisoned, the symptoms are very severe and can lead to chronic liver problems.  Do not consider eating any mushrooms containing Gyromitrin.

Found in species of False Morels, especially Gyromitra esculenta, Elfin Saddles (Helvella) and Verpa.  

The Gastrointestinal Irritants: The most common form of mushroom poisoning involves a course of nausea, vomiting, cramps and diarrhea and all the feelings of malaise that accompany the symptoms.  The onset of symptoms is between 30-90 minutes, and typically lasts from 3-12 hours.  Certainly a severe episode can linger for several days or more before complete recovery.  The mushrooms known for causing a GI reaction are found in many families and genera and in many cases, the chemical nature of the toxin has never been determined.  In some groups a GI poisoning can be the result of consuming an edible mushroom raw or undercooked; in these cases, the toxins are neutralized by the heat of cooking.

The mushrooms most commonly causing GI distress in the Northeast include various species in the Agaricus Boletes, Entoloma, Hebeloma, Lactarius, Naematoloma, Omphalotus, Russula, Scleroderma, Tricholoma and many others.  In more southern areas of New England and south, the green-spored Lepiota, Chlorophyllum molybdites, is the most common species causing GI distress.

The Psychoactives  are so named because their ingestion triggers a change in states of consciousness including inebriation, giddiness, visions and hallucinations.   Plants and fungi containing psychoactive compounds have been used ritually and as inebriants the world over, but when taken unintentionally, they are considered toxic.

Psilocybin and related indoles: Someone who has eaten psilocybin-containing mushrooms has onset of symptoms in 30-60 minutes and they last 5-6 hours with major implications to the central nervous system.   Victims feel giddy and euphoric, have a loosening of associations and a heightened sense of visual and auditory stimuli.  They may have visual and auditory hallucinations and a sense of being integrated with  a larger universe.  These are often described as a mystical experience.  Some people, on the other hand, become anxious and paranoid and face the risk of a “bad trip”.  Symptoms generally fade after 4-6 hours.  The indoles include LSD, a far more potent hallucinogen derived from the fungus ergot.

Mushrooms containing Psilocybin and related compounds are found in certain species of the Psilocybe, Gymnopilus,  Paneolus, Conocybe genera.  These are sometimes referred to as psychedelic or magic mushrooms.

Ibotenic Acid and Muscimol:  Though not as well studied as the psilocybin mushrooms, the species of Amanita mushrooms that contain


The beautiful Fly Amanita was used as an inebriant and ritual mushroom in days past.

these compounds have been used in ceremony and celebration across much of eastern Europe and Eurasia for hundreds of years (at least).  Symptoms generally begin 30-90 minutes after ingestion and include uncoordination or a drunken gait, nausea and vomiting, and alternating periods of agitation and activity and a deep sleep that is difficult to rouse.  People may have visions or hallucinations as well.   Severe intoxication can occur but life-threatening illness is quite rare.  As with the psilocybin mushrooms, risk of serious injury or the very rare death is more commonly associated with out of control behavior associated with intoxication.

These compounds are found in several species of Amanita, most notoriously, A. muscaria, the Fly Mushroom.   

Muscarine  Muscarine is named for Amanita muscaria where it was first identified.  The symptoms of muscarine poisoning are well known enough to have generated an acronym; PSL, meaning perspiration, salivation  and lacrimation, are the most distinctive symptoms.  These are often accompanied by nausea, vomiting, diarrhea and sometimes with tightly constricted pupils, blurred vision and  cramping of the muscles.  Symptom onset is very rapid, generally within 30 minutes of ingestion.  Muscarine is the only toxin for which there is an effective antidote.  An injection of atropine will rapidly reverse symptoms.  Severe poisonings of muscarine can trigger lowered blood pressure and heart rate and convulsions, and have been responsible for a few deaths worldwide.

Muscarine is most common in the genera Inocybe and Clitocybe and is responsible for some of the symptoms of Jack-O’lantern poisoning.  It occurs in very low levels in Amanita muscaria and is not a significant factor in Fly Agaric poisonings.

Coprine (Anabuse-like Reaction):  There exist a few otherwise edible mushrooms that trigger illness only if the diner consumes an alcoholic beverage during or following eating the mushrooms.   Symptoms begin 30-60 minutes after eating, and are identical to those produced by disulfiram (Antabuse)when combined with alcohol. Hot flushes of the face and neck, metallic taste in mouth, tingling sensation in limbs, numbness in hands, palpitations, a throbbing headache, nausea and vomiting. Although unpleasant, consumption of mushroom is not fatal.  The best known mushroom is called the Tippler’s Bane or Alcohol Inky, Coprinus atramentarius, and is considered a desirable edible by those not inclined to imbibe.  The toxins are also found in several species of Coprinus (Coprinellus), and a few Clitocybe.  There are a number of mushrooms that occasionally cause problems for people when consumed with alcohol, including morels.


Knowing the poisonous mushrooms that are common in your region is as important as learning the edible ones and is a vital step in safe foraging.  If a common edible has a toxic species which it resembles, become 100% comfortable in identification of both before ever considering eating the good one.   For additional information on these and other Northeast mushrooms responsible for poisoning and how to stay safe, please get a copy of my book Chanterelle Dreams, Amanita Nightmares, available here.


Amanita muscaria

One of the more beautiful toxic mushrooms; The Fly Agaric

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