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Mushroom (Toadstool) Poisoning


Gerald F. O’Malley

, DO, Grand Strand Regional Medical Center;

Rika O’Malley

, MD, Grand Strand Medical Center

Reviewed/Revised May 2022 | Modified Sep 2022

Many species of mushroom are poisonous and can cause different symptoms depending on the type of mushroom.

  • Different species of mushrooms produce different toxins with different effects.

  • Even within the same species, the potential for poisoning may vary at different times of the growing season and with cooking.

  • It is difficult even for knowledgeable people to differentiate poisonous from nonpoisonous mushrooms—folklore rules are unreliable.

  • Because it can be hard to identify the mushroom people ate, doctors usually just treat people based on their symptoms.

All poisonous mushrooms cause vomiting and abdominal pain. Other symptoms vary greatly depending on mushroom type. Generally, mushrooms that cause symptoms early (within 2 hours) of ingestion are less dangerous than those that cause symptoms only later (usually after 6 hours).

Did You Know...

  • Mushrooms that cause symptoms early (within 2 hours) of ingestion are usually less dangerous than those that cause symptoms only later (after about 6 hours)

Early gastrointestinal symptoms

Mushrooms that cause early gastrointestinal symptoms (such as Chlorophyllum molybdites and the little brown mushrooms that often grow on lawns) cause vomiting and diarrhea, typically within 1 to 6 hours. The diarrhea is occasionally bloody. Some people have headaches or body aches. Symptoms usually go away within 24 hours.

Early symptoms that affect the brain and spine

Mushrooms that cause early symptoms that affect the brain and spinal cord include hallucinogenic mushrooms, which contain the hallucinogen Hallucinogens Hallucinogens are a class of drugs that cause profound distortions in people's perceptions. Hallucinogens distort and intensify sensations, but the actual effects are variable and unpredictable... read more psilocybin. The most common are members of the Psilocybe genus, but some other mushrooms also contain psilocybin. They also cause nausea and vomiting within 15 to 45 minutes of ingestion. Symptoms begin within 20 to 90 minutes of ingestion and include euphoria, enhanced imagination, and hallucinations. A rapid heartbeat and high blood pressure often develop, and some children develop a fever. However, these symptoms go away without treatment, and serious consequences are rare, so specific treatment is usually not needed. However, if the person is very agitated, the doctor may give a sedative (such as lorazepam).

Early symptoms caused by muscarine-containing mushrooms

In poisoning caused by many species of Inocybe and some species of Clitocybe, the toxic substance is muscarine. Muscarine is a chemical that mimics acetylcholine, which is one of the substances the body uses to send messages between nerves (a neurotransmitter). Symptoms, which begin within 30 minutes after eating, may include

  • Increased tearing and salivation

  • Narrowing (constriction) of the pupils

  • Sweating

  • Vomiting, stomach cramps, diarrhea

  • Dizziness

  • Muscle twitching (fasciculations)

  • Confusion, coma, seizures (occasionally)

Although some of these symptoms are serious, most people have only mild symptoms that go away within 12 hours. People with severe symptoms are given intravenous atropine, a drug that blocks acetylcholine, and nearly all people recover in 24 hours. Without treatment, death can occur in a few hours with severe poisoning.

Delayed gastrointestinal and other symptoms

Mushrooms that cause delayed gastrointestinal symptoms include Amanita phalloides and related types of mushroom (members of the Amanita, Gyromitra, and Cortinarius genera).

Amanita phalloides causes 95% of mushroom poisoning deaths. Vomiting and diarrhea start in 6 to 12 hours. Sometimes the blood sugar level drops dangerously low (hypoglycemia Hypoglycemia Hypoglycemia is abnormally low levels of sugar (glucose) in the blood. Hypoglycemia is most often caused by medications taken to control diabetes. Much less common causes of hypoglycemia include... read more ). Symptoms subside for a few days, but then people develop liver failure Liver Failure Liver failure is severe deterioration in liver function. Liver failure is caused by a disorder or substance that damages the liver. Most people have jaundice (yellow skin and eyes), feel tired... read more and sometimes kidney failure Overview of Kidney Failure Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney failure has many possible causes. Some lead to a rapid decline in kidney function... read more . Liver failure causes the skin to turn yellow (jaundice). People with kidney failure may have reduced urination or may have stopped urinating. Sometimes the symptoms disappear on their own, but about half of the people who have this type of poisoning die in 5 to 8 days. People with liver failure may survive if given a liver transplant Liver Transplantation Liver transplantation is the surgical removal of a healthy liver or sometimes a part of a liver from a living person and then its transfer into a person whose liver no longer functions. (See... read more .

Amanita smithiana mushrooms tend to cause delayed vomiting and diarrhea (about 6 to 12 hours after they are eaten). Kidney failure can occur within 3 days to 1 or 2 weeks after the mushrooms are eaten, and people often need temporary hemodialysis Hemodialysis Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons... read more Hemodialysis .

Gyromitra mushrooms also cause delayed vomiting and diarrhea and a low blood sugar level. Other problems include brain toxicity (such as seizures) and, after a few days, liver and kidney failure.

Most Cortinarius mushrooms originate in Europe. Vomiting and diarrhea may last for 3 days. Kidney failure, with symptoms of flank pain and a decreased amount of urine, may occur 3 to 20 days after the mushrooms are eaten. Kidney failure often resolves spontaneously.

Several mushroom species (such as Tricholoma and Russula) are responsible for delayed muscle breakdown (rhabdomyolysis Rhabdomyolysis Rhabdomyolysis occurs when muscle fibers damaged by disease, injury, or toxic substances break down and release their contents into the bloodstream. Severe disease can cause acute kidney injury... read more ), which is fatal in some cases. There is no specific treatment, so doctors concentrate on treating specific symptoms and making people comfortable.

Some other mushroom species (such as Clitocybe, Hapalopilus rutilans, and Pleurocybella porrigens) cause brain and nerve disorders, including numbness to burning of the hands, fingers, feet, and/or toes, dizziness, difficulty seeing, altered consciousness, seizures, respiratory failure, and death.

More Information

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

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