Home / Food Safety / Mushroom Poisoning

Mushroom Poisoning

Every year across the United States, more than 8,000 cases of mushroom ingestions are reported to the American Association of Poison Control Centers.

Children under the age of 6 years account for a majority of these cases.

Fortunately, the majority of these poisonings result in minor health effects, if any; however, mushroom ingestions can be very serious and emergency treatment may be required.

  • In the United States, there are about 5,000 types of mushrooms, thus making identification of a specific mushroom very difficult.
  • Of these 5,000 or so mushrooms, about 100 are responsible for most of the cases of mushroom poisoning.
  • In 2004, the type of mushroom ingested was unknown in 95% of cases reported to poison control centers (it is close to impossible to identify a mushroom based on description over the phone).
  • Telling the difference between a poisonous mushroom and an edible mushroom is extremely difficult.
  • All mushrooms not bought at the grocery store are considered to be potentially dangerous and should not be eaten.

Mushroom Poisoning Facts

  1. Signs and symptoms of mushroom poisoning may not occur right after ingestion; illness could be delayed for hours or even days.
  2. Some people can eat mushrooms with no problems, while other people eating the same mushroom will experience severe symptoms.
  3. Some mushrooms are poisonous when raw but become harmless when parboiled and thoroughly cooked.
  4. Some mushrooms are poisonous regardless of how they are cooked or prepared.
  5. Some mushrooms are poisonous only if eaten with alcoholic beverages.
  6. Some mushrooms are considered poisonous because they are hallucinogenic.
  7. Some mushrooms that are edible when fresh and young become poisonous when they are older.
  8. Some mushrooms are poisonous in one part of the country and are not poisonous in another.

Signs and symptoms of mushroom poisoning may not occur right after ingestion; illness could be delayed for hours or even days.

There are a variety of mushrooms, divided into categories or groups. Each category causes different symptoms.

Group 1

The mushrooms in this group are some of the most deadly.
A couple examples include Amanita phalloides (the Death Cap) (see photo called Amanita phalloides) and Amanita verna (see photo called Amanita verna).

A common clinical finding of mushroom poisoning from this group is the delayed onset of symptoms.

  1. Nausea, vomiting, cramping abdominal pain, and severe diarrhea usually begin within 6 to 12 hours after ingestion.  This can lead to severe dehydration.
  2. The intestinal symptoms can last up to 24 hours and thereafter the patient may feel improved.
  3. In 3 – 4 days, abnormal blood tests suggesting liver damage along with features of liver failure such as jaundice (yellow skin color changes), lethargy, seizures, coma, and abdominal pain over the liver can occur.Kidney failure with decreased urine output also occurs.Death may occur and children are susceptible.

Group 2

This group includes the False morel mushrooms (e.g., Gyromitra species).

Although rare poisonings, they can be fatal.

These mushrooms are found on the ground or on rotten wood, are
orange-brown to brown, have no gills, and have convoluted brainlike
caps that are occasionally saddle-shaped (see photo called
Gyromitra and Gyromitra 2)

Symptoms start anywhere from 2-12 hours after ingestion (usually 5 -10 hours)

The symptoms include:

nausea and vomiting
watery (or bloody) diarrhea
muscle cramps
abdominal pain

Severe cases can include:

liver damage
high fever
death (usually two to four days after ingestion)

Group 3

This group is known as the Muscarine-containing mushrooms and include the Clitocybe and Inocybe species (see photo called Inocybe species)

Symptoms start anywhere from 30 minutes to 2 hours after ingestion.

The symptoms for this poisoning are:

profuse, prolonged sweating
small pupils
vomiting and diarrhea
slow pulse and low blood pressure in severe cases

Victims usually recover within 24 hours but death may occur.

Group 4

This group is known as the Coprine-containing mushrooms

These mushrooms are also known as the Inky caps because although they begin light gray, they eventually blacken as they turn into ink and disintegrate (see photo called Coprinus atramentarius).

Toxicity can result if alcohol is ingested within 72 hours of mushroom ingestion.

Onset of symptoms usually within 30 minutes of ingestion.
Usually the symptoms of poisoning resolve on their own over a few hours.

The symptoms include:

hot and sweaty face, becoming flushed
flushing spreading to the neck and chest
rapid, difficult breathing
rapid heart rate
bad headache
nausea and vomiting

Group 5

These mushrooms contain ibotenic acid and muscimol

Examples include Amanita muscaria (see photo called Amanita muscaria) and Amanita pantherina

Onset of symptoms is typically 30 minutes to 2 hrs after ingestion and are usually short lived.

The primary symptoms are:

alcohol intoxication-like state
visual disturbance
deep sleep then follows
seizures may occur, especially in children

Group 6

These are the hallucinogenic mushrooms that alter consciousness

They contain the toxin, Psilocybin (see photos called Psilocybin 1, 2 and 3)

Onset of symptoms is usually within one hour of ingestion and last 4 – 6 hours.

The primary symptoms are:

an unsteady walk
compulsive movement
fast heart beat
dilated pupils
fever and seizures possible in young children

Group 7

These mushrooms are considered gastrointestinal irritants, meaning they cause an upset stomach.

This is the largest group of mushrooms.

Two examples are in the photo gallery (see photo called Boletus species and Chlorophyllum molybdites)

Onset of symptoms usually within 30 – 90 minutes after ingestion with improvement 6 – 24 hours later.

Symptoms include:

abdominal pain

Group 8

These mushrooms contain the toxin Orellanine

Cortinarius species are found in this group (see photo called Cortinarius species)

Onset of symptoms may be delayed for 1 – 3 weeks after ingestion.

Symptoms include:

frequent urination
burning thirst
progression to kidney failure (dialysis required)

Group 9

Amanita smithiana is the mushroom in this group

Mushrooms are similar in appearance to edible mutsutake (see photo called Amanita smithiana)

Onset of symptoms is typically 4 to 12 hours after ingestion.

Symptoms include:

liver and kidney problems

Group 10

Tricholoma equestre
The mushroom is a smooth, yellowish-brown, or greenish-brown capped fungus with yellow gills (see photo called Tricholoma equestre)

The toxin in this mushroom affects the muscles of the body, including the heart.

After ingestion, it takes 24-72 hours before the following symptoms are present:

muscle weakness
muscle cramps
facial redness
death is possible

What can I do if my child has eaten a mushroom?

If your child has eaten a wild mushroom, you can take several simple steps.

  • Collect the mushrooms your child was eating.
  • A few should be carefully dug up so that even the underground parts can be saved for identification.
  • The whole mushroom can then be shown to your child’s doctor, which might help your doctor know whether the mushroom was poisonous or not.
  • If you find more than one kind of mushroom around your child, collect all of the different kinds that your child might have eaten.
  • Call your doctor or the Poison Control Center (1-800-222-1222) for advice.
  • Poison Control Centers can consult with a mushroom specialist to help identify the mushroom.

How can mushroom poisoning in my child be prevented?

  • Check your yard for mushrooms before letting young children out to play.
  • Teach children not to taste or even touch ANY outdoor mushrooms.
  • Don’t add mushrooms from the wild to your gourmet dishes unless you are absolutely positive that the mushroom has been accurately identified and is safe.