California health officials are warning people not to eat foraged wild mushrooms after nearly two dozen people were sickened — including one fatality — by the highly poisonous death cap mushroom (Amanita phalloides). The California Department of Public Health (CDPH) reported 21 confirmed cases between mid-November and last Friday, with toxins causing one death, severe liver damage in children and adults, several intensive-care admissions, and at least one person potentially needing a liver transplant.
Clusters of cases have been reported in the Monterey and San Francisco Bay areas, but state officials warn the risk exists across California. CDPH director Dr. Erica Pan advised the public not to forage for wild mushrooms during the high-risk season because death caps are easily mistaken for edible varieties. An unusually rainy fall and winter has created favorable conditions for fungal growth.
Origin and range
Death caps originated in Eurasia and were likely introduced to parts of California decades ago, probably via imported European oak roots. They’ve since become established in many regions worldwide. The species is responsible for a large share of fatal mushroom poisonings globally and has been reported in the Midwest, Northeast, Mountain West and other areas of the U.S.
Where they grow and who’s at risk
Death caps typically grow near oak, pine and other hardwood trees, often in urban and suburban wooded areas rather than deep forests. They often appear in small, dispersed groups in places where people and pets encounter them, making them a particular public-health concern.
Identification and danger
Young death caps (the “button” stage) can closely resemble safe edible mushrooms like puffballs. Typical features include a greenish-gray cap that flattens with age, white gills, a white ring on the stem, and a large white sac (volva) at the stem base. They can reach about 6 inches across and tall. The mushroom can smell and taste pleasant, giving no warning of its toxicity.
A very small amount—half a cap or less—can be lethal. Mortality after ingestion can be high without prompt treatment, and scientists estimate death caps cause thousands of illnesses and many deaths worldwide each year.
Toxin and clinical course
Death caps contain a stable, highly toxic peptide called α-amanitin (AMA), resistant to heat, freezing and stomach acid. Symptoms are classically delayed: nausea, severe abdominal pain, vomiting, watery diarrhea and extreme thirst typically begin six to 15 hours after ingestion but can occur up to 48 hours later. After an initial phase that may last about a day, a deceptive period of apparent improvement can be followed by rapid and severe liver, kidney and other organ damage, potentially progressing to coma and death within days.
Treatment and prognosis
There are limited effective treatments. Medical care focuses on rapid supportive treatment: activated charcoal if seen early, aggressive fluid and electrolyte management, and medications used in some cases such as high-dose penicillin and silibinin (from milk thistle). In severe poisoning, liver transplantation may be required. Research is ongoing into better antidotes; laboratory studies have suggested potential benefit from certain existing drugs, but human data remain limited.
What to do
– Do not forage wild mushrooms unless you are an expert; during outbreak conditions, avoid foraging entirely.
– Only consume mushrooms bought from reputable commercial sources.
– If you or someone else develops gastrointestinal symptoms after eating foraged mushrooms, seek medical attention immediately and tell clinicians about possible mushroom exposure. Early care improves chances of survival.
– Keep pets away from wild mushrooms and seek veterinary care promptly if ingestion is suspected.
Because death caps are common in many areas and can be mistaken for edible species, authorities urge caution and prompt medical attention for any suspected exposures.