Background
Amatoxin-containing mushrooms are unexpectedly blooming beyond normal seasonal expectations across parts of Northern California, Central Coast California, and Southern California following recent spring rains. While Western Destroying Angels typically bloom into spring, the Death Caps typically decline by late winter. However, abnormal environmental conditions such as the continued rains in recent weeks, are likely contributing to the unusually robust resurgence of these poisonous mushrooms in the late spring. Because they closely resemble several edible mushroom varieties at different stages of growth, even individuals with foraging experience have encountered difficulty distinguishing them from safe-to-eat varieties. Both Death Cap and Western Destroying Angel mushrooms contain potentially deadly amatoxins that are not removed by boiling, cooking or drying the mushrooms before consumption. CDPH is urging individuals to avoid picking and eating wild mushrooms while risk of potentially deadly amatoxin poisoning is high.
Amatoxin poisoning from accidental consumption of these toxic mushrooms in this ongoing outbreak has led to unprecedented numbers of serious illnesses and deaths, with four adult fatalities and four liver transplants to date. Eight cases have been reported in the last four weeks (with four of the eight reported in the last week), in a time frame past the normal peak season. In a typical year fewer than 5 cases are reported (Albertson et al., 2023). In total between November 18, 2025, and May 11, 2026, California Poison Control System (CPCS) identified 47 cases in a stretch of Northern California and the Central Coast ranging from Humboldt to San Luis Obispo and east to Sacramento and Yuba Counties (Figures 1 and 2 below). Though most clusters have been reported in the Monterey and San Francisco Bay Areas, there is risk statewide. Medical treatment for patients with amatoxin poisoning has been provided in the following counties: Alameda, Contra Costa, Humboldt, Monterey, Sacramento, San Francisco, San Luis Obispo, San Mateo, Santa Clara, Santa Cruz, Sonoma, and Yuba counties (Figure 2 below).
The 47 known amatoxin poisoning cases range in age from 19 months to 84 years, with both linked cases (family groups) and individual cases. Affected individuals are known to speak Spanish, Mam (indigenous Mayan language) , Mixteco (indigenous language in Mexico), Mandarin Chinese, Ukrainian, Russian, and English highlighting the need for multilingual outreach. Among those who reported a preferred language, the majority identified Spanish as their preferred language. Two affected individuals were unhoused.
Amatoxin-containing mushrooms (Death Caps and/or Western Destroying Angels) have been foraged in locations that range from neighborhoods and local parks to regional parks and recreation spaces, nature preserves, and at least one national park. Both types of poisonous mushrooms grow on the ground in relationship with tree root systems. Death Caps, an invasive species in California, can be found adjacent to many types of trees, especially oaks, but have been found among pines while the California native Western Destroying Angels are typically found adjacent to oaks. As information about specific locations associated with new cases and/or reported sightings becomes available, CDPH is sharing details with local health jurisdictions and parks and recreational contacts in those areas.
CDPH is continuing to coordinate with CPCS and public health partners on case investigation and tracking as well as outreach and education. In response to the ongoing outbreak of severe illnesses associated with the consumption of amatoxin-containing mushrooms, CDPH has developed information materials including a multi-language warning poster and warning flyers in nine languages as well as three public service announcements (PSAs)—one in English, one in Spanish, and one in Mixteco (with assistance from the County of San Luis Obispo Health Agency). These PSAs warn the public about the risks of mushroom hunting during this high-risk season with abundant Death Cap mushrooms. CDPH has also developed webpages in English and Spanish on poisonous mushrooms. The webpages now include updated information on the current case count, timeframe, counties with hospitalizations, and the languages among those affected for the outbreak. Additionally, the webpage includes a data dashboard link for public health professionals that provides updated information including a case definition, an epidemic histogram of the outbreak, and selected case characteristics.
Recommendations
Medical Professionals
Any patient who presents with recent or active gastrointestinal symptoms or elevation of liver enzymes should be asked about possible consumption of foraged wild mushrooms, including unknown mushrooms or any mushrooms that could potentially have been Death Cap and/or Western Destroying Angel mushrooms. If any remaining specimen or photos of the mushrooms are available, CDPH can assist with potential identification; even information about what mushroom the patient believed they were eating can be informative. Consumption of foraged wild mushrooms in this high-risk season warrants careful evaluation for amatoxin poisoning and consideration for hospital admission.
Remind patients to avoid mushroom hunting/foraging while risk of amatoxin poisoning is high.
Continue to follow guidance in the initial December 5, 2025 health advisory for treatment of potential amatoxin poisoning cases. Obtain early consultation with a medical toxicologist with expertise in managing patients with mushroom poisoning. Contact CPCS (1-800-222-1222) to report cases of illness after consumption of amatoxin-containing mushrooms and/or for advice on medical management of these patients.
Testing: CDPH has been able to assist with rapid amatoxin detection in the urine in some recent cases and can also assist with laboratory analyses of mushroom specimens – contact the CDPH Laboratory Response Network's CT Training and Outreach Coordinator, Terri Jackson at (530) 304-7439 or Terri.Jackson@cdph.ca.gov.
Public Health Professionals
Continue to evaluate the risk level in your area – it may change over time, especially with rain events, such as the recent late spring rains. Regional and local mycological societies can be useful resources. See https://bayareamushrooms.org/california_clubs.html and https://namyco.org/clubs/ for directories of such organizations.
Continue to advise residents to avoid picking and eating wild mushrooms while risk of amatoxin poisoning is high. Share educational materials on Death Cap and Western Destroying Angel mushrooms with communities.
Continue to work with local partners to identify and report cases and minimize exposure. Consider coordination with local healthcare systems, and community groups who have a cultural tradition of foraging food from their environments, outreach to foraging groups, coordination with veterinarians and animal health services, as well as coordination with parks departments to post advisories in public spaces where these mushrooms may be found.
Californians
Avoid picking and eating wild mushrooms or eating food prepared with wild mushrooms while risk of amatoxin poisoning is high. If you do participate in “mushroom hunting" or foraging, rely on local expert knowledge for identification rather than apps or websites. Foragers are encouraged to document mushrooms consumed with informative photos and location information.
Buy mushrooms from trusted grocery stores and retailers. Take care when buying mushrooms from street vendors.
Keep pets away from wild mushrooms – animals can be poisoned too. There have been several reports of dog deaths related to amatoxin poisoning during this outbreak.
Seek help immediately, if you or someone you know has eaten a poisonous mushroom. Do not wait for symptoms to appear. Treatment is more difficult once symptoms start.
Resources
CDPH has developed materials in multiple languages to support amatoxin-containing mushroom education and outreach efforts, including:
CPCS has developed materials in multiple languages to support amatoxin-containing mushroom education and outreach efforts:
References
Albertson, T.E., Clark, R.F., Smollin, C.G., Vohra, R., Lewis, J.C., Chenoweth, J.A. and Stocking, J.C., 2023. A ten-year retrospective California Poison Control System experience with possible amatoxin mushroom calls. Clinical Toxicology, 61(11), pp.974-981.
Peredy, T.R. Amatoxin-containing mushroom poisoning (eg, Amanita phalloides): Clinical manifestations, diagnosis, and treatment. In: UpToDate. Last updated March 25, 2024. https://www.uptodate.com/contents/amatoxin-containing-mushroom-poisoning-eg-amanita-phalloides-clinical-manifestations-diagnosis-and-treatment
Horowitz, B.Z. et al. Mushroom Toxicity. In: Medscape: Tools & Reference: Emergency Medicine. Last updated November 11, 2025. https://emedicine.medscape.com/article/1008902-overview
Amanita phalloides Mushroom Poisonings — Northern California, December 2016. Vo, K.T. MMWR Morb Mortal Wkly Rep 2017; 66:549-553.
Monterey County. 2025. Health Advisory: Severe Hepatotoxicity Following Consumption of Wild Mushrooms. December 1, 2025. https://www.countyofmonterey.gov/Home/Components/News/News/11687/
CDPH. 2025. Health Advisory: Severe, Potentially Fatal Liver Damage in Children and Adults Associated with Consumption of Foraged Wild Mushrooms. December 5, 2025. https://www.cdph.ca.gov/Programs/OPA/Pages/CAHAN/Foraged-Wild-Mushrooms.aspx
CDPH. 2026. Health Advisory: Severe illness or fatal liver damage caused by mushroom poisonings in California . January 15, 2026. https://www.cdph.ca.gov/Programs/OPA/Pages/CAHAN/Increase-in-mushroom-poisonings-in-California%E2%80%8B%E2%80%8B-.aspx
CDPH. 2016. Use Caution When Collecting, Eating Wild Mushrooms. Press Release. Last updated March 22, 2017. https://www.cdph.ca.gov/Programs/OPA/Pages/NR16-077.aspx
Figure 1: Case count over ongoing amatoxin-containing mushroom poisoning outbreak
Figure 2: Map indicating counties where hospitals have provided treatment in the ongoing outbreak
![Map indicating counties where hospitals have provided treatment in the ongoing outbreak]()
Figure 3: Outreach Material Examples
