Death Cap Mushroom Poisonings in Northern California, 2025–2026

Summary

• Already known: some toxic mushrooms look like edible ones, and foragers mistake them. Eating mushrooms containing amatoxins can cause liver failure and death.
• This report: from November 2025 to March 2026, the California Poison Control System (CPCS) and California Department of Public Health (CDPH) responded to 39 amatoxin poisonings in Northern California — three liver transplants and four deaths. Many patients had foraged look-alike mushrooms in other countries, and together they spoke at least six languages besides English.
• Implication: eating foraged mushrooms is high-risk, especially in rainy seasons; education in many languages may prevent poisonings.

The outbreak

• The trigger: above-average rain in late November 2025 set off very large "superblooms" of Amanita mushrooms in San Francisco Bay Area parks and wildlands. The genus has about 600 species — many edible, some among the world's deadliest.
• First cases: on November 16, a man aged 36 and his sister aged 38 came to an emergency department with abdominal pain, nausea, vomiting and diarrhea, 4 days after eating mushrooms a relative had foraged. CPCS suspected amatoxin poisoning on November 18; both recovered.
• Unusual size: CPCS normally sees fewer than five suspected cases a year; it had 11 in November 18–29 alone. Over 17 weeks (to March 17, 2026) there were 39.
• Outcomes: 32 (82%) recovered, three (8%) needed liver transplants, and four (10%) died — the largest outbreak of mushroom liver poisoning in California history and in the U.S. in several decades. (The previous large one, in December 2016, had 14 cases.)

Who was poisoned

• Deaths: a man aged 45 who ate mushrooms foraged in a national park (two relatives who ate less survived); a man aged 49 who ate mushrooms like ones he had eaten in Mexico; a man aged 29 who ate 20 mushrooms, was sent home with a diagnosis of gastroenteritis, returned the next day and died 4 days later; and a man aged 67 who ate one large mushroom.
• Western destroying angel: a family of four (two adults aged 32, children aged 8 and 6) and a person aged 28, foraging 150 miles (241 km) apart, ate Amanita ocreata — the first outbreak of this size to include it. They fell ill 8–12 hours after eating.
• Found mushrooms: a woman aged 37 experiencing homelessness ate mushrooms left in a bag on a garbage can; urine testing by CDPH's Laboratory Response Network for Chemical Threats confirmed amatoxin. She recovered.
• Languages: Spanish, Mixteco, Mam, Ukrainian, Russian and Mandarin Chinese. Two patients were unhoused, and one ate the mushrooms because of food insecurity.

The response

• December 5: a statewide health advisory on recognizing and treating amatoxin poisoning.
• Posters in every identified language (materials): don't forage wild mushrooms; they can cause liver failure and death; poisonous and edible species look alike; how to get help — shared on social media and with mycological societies, parks, and places where the mushrooms grew or poisonings happened.
• Outreach with local health officers, hospitals, Spanish-language TV and radio, and community groups.

About amatoxin poisoning

• Deadly: amatoxin mushrooms cause >90% of mushroom-poisoning deaths worldwide, and 10%–20% of poisonings are fatal even with treatment.
• The species: the death cap (A. phalloides), which causes the most deaths, is native to Europe and likely arrived in contaminated soil; A. ocreata is native across California. Both grow in urban parks and coastal live oak woodlands, peaking October–April.
• Cooking doesn't help: amatoxins survive cooking, and symptoms are delayed.

• Treatment: no standard regimen and no FDA-approved therapy. Aggressive IV fluids; N-acetylcysteine and high-dose penicillin G (both off-label) and silibinin, a milk-thistle extract available through the FDA's Emergency Investigational New Drug program; weaker evidence for activated charcoal, cyclosporine, octreotide and biliary drainage.
• Diagnosis: depends on asking about foraged mushrooms, identification by a mycologist, and field tests such as spore prints; urine testing is limited to specialized labs.

What's needed

Outreach on the dangers of foraging, clinician education to spot amatoxin poisoning behind vague stomach symptoms and liver injury, and poison control centers as an early warning system. CDPH is working to make amatoxin poisoning reportable in California.

Sources

Based on "Amanita Species Mushroom Poisonings — Northern California, November 2025–March 2026," by Kevin J. Brandecker, Chelsea Hayman, Kathy T. LeSaint, Rais Vohra, Asha Choudhury, M. Elizabeth Marder, Russell Bartlett, Tracy Barreau and Craig G. Smollin, of the California Poison Control System, the University of California, San Francisco, the California Department of Public Health and CDC, Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention; a work of the United States government in the public domain. The report's photographs of the two species, credited to the California Department of Public Health, are left out.