Article Source: County of San Mateo - CA
San Mateo County Health Warns Public About Deadly Wild Mushroom Poisoning
January 15, 2026
San Mateo County Health is warning residents about the serious and
potentially deadly risks of eating wild, foraged mushrooms following
the illness of a San Mateo County resident linked to death cap mushroom
poisoning.
Recent rain has contributed to the widespread growth of death cap
mushrooms in California. The California Department of Public Health
(CDPH) advises the public to avoid picking and eating wild mushrooms
during this high-risk season. Death cap mushrooms, which are currently
widespread in parts of Northern California and the Central Coast,
contain amatoxins that can cause severe liver damage and death. These
mushrooms are often found near trees such as oaks and pines and can be
easily mistaken for edible varieties and also pose a risk to pets that
may ingest them while outdoors.
“Death cap mushrooms are extremely dangerous and can be mistaken for
mushrooms that look safe to eat. No amount of cooking, boiling or
drying makes these mushrooms safe,” said Dr. Kismet Baldwin-Santana,
San Mateo County Health Officer. “We recognize that mushroom
hunting is a valued activity. However, the safest choice right now is
to avoid eating any wild mushrooms. Even experienced foragers should
exercise extreme caution and should not rely on AI-assisted field
identification to distinguish between safe and poisonous mushrooms.”
Death cap mushrooms
Death Cap mushrooms (Amanita Phalloides) at different stages of development.
Amatoxin poisoning from accidental consumption of toxic mushrooms has
resulted in unprecedented numbers of serious illnesses and deaths in
the state. The California Department of Public Health and the
California Poison Control System report three adult fatalities and
three liver transplants between Nov. 18, 2025 and Jan. 6, 2026.
Thirty-five cases were identified across Northern California and the
Central Coast, ranging from Sonoma to San Luis Obispo. In a typical
year, fewer than five cases are reported.
Symptoms of death cap mushroom poisoning can
begin six to 24 hours after eating the mushrooms and may include watery
diarrhea, nausea, vomiting, abdominal pain and dehydration. Symptoms
may briefly improve before severe liver failure develops one to four
days later.
CDPH strongly advises residents to only consume mushrooms purchased
from reputable stores or known commercial sources and to avoid all wild
mushrooms foraging during this season.
Anyone who may have eaten a wild mushroom or is experiencing symptoms should seek medical care immediately. The California Poison Control is available 24 hours a day to provide expert guidance at 1-800-222-1222.
For the latest information and safety guidance, residents are
encouraged to follow updates from the California Department of Public
Health. The agency has released statewide data linking death cap
mushrooms to three deaths, three liver transplants and 35
hospitalizations.
Faizus Amin
Public Information Officer
San Mateo County Health
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