The California Department of Public Health is raising the alarm on an outbreak of potentially deadly mushrooms, which has hospitalized dozens of people and resulted in several deaths.

Due to recent rain across Northern and Central California, the region has seen a bloom of Amanita phalloides, also known as "death cap mushrooms," which are commonly mistaken for edible mushrooms but can cause amatoxin poisoning if consumed.

As of Jan. 6, the California Poison Control System has recorded 35 hospitalized cases of people from as young as 19 months to 67 years old who were poisoned by consuming wild and foraged mushrooms. Three adults have died due to the mushrooms, and three people needed liver transplants as a result of the poison.

"Death cap mushrooms contain potentially deadly toxins that can lead to liver failure," Dr. Erica Pan, CDPH Director and State Public Health Officer, said in a press release in December 2025. “Because the death cap can easily be mistaken for edible safe mushrooms, we advise the public not to forage for wild mushrooms at all during this high-risk season.”

The CPCS identified cases across Northern California and the Central Coast, including Alameda, Contra Costa, Monterey, San Francisco, San Luis Obispo, San Mateo, Santa Clara, Santa Cruz, and Sonoma counties. The department noted that most cases have occurred in the Monterey and San Francisco Bay Areas.

“A single bite of the mushroom could cause significant toxicity,” Dr. Craig Smollin, medical director for the San Francisco Division of California Poison Control System, told SFGate during a press conference. “I also want to just stress that there’s nothing, there’s no cooking of the mushroom or freezing of the mushroom, that would inactivate the toxin.”

Smollin also noted that this was potentially the "largest outbreak" California had recorded.

What can Californians do to prevent getting sick?

The California Department of Public Health is advising people to avoid picking and eating wild mushrooms during this high-risk season, as death cap mushrooms are abundant across the Northern California and the Central Coast regions.

Death cap mushrooms can be found growing near oak trees, other hardwoods and sometimes pine trees. ​

It's recommended that consumers purchase their mushrooms from "trusted grocery stores and retailers."

If an individual believes they have consumed a poisonous mushroom, initial symptoms could include watery diarrhea, nausea, vomiting, abdominal pain, and dehydration, which can occur within 6 to 24 hours of eating a toxic mushroom.

Symptoms typically resolve within a day, according to the California Department of Public Health. But this may be a brief improvement, as people could still develop serious to fatal liver damage within 48 to 96 hours after consumption.

If a person believes they have eaten a toxic mushroom, it is recommended that they call the California Poison Control System hotline at 800-222-1222 and not wait for symptoms to appear.

Noe Padilla is a reporter covering Sacramento and Northern California for the USA TODAY Network. Reach him at npadilla@usatodayco.com.

This article originally appeared on USA TODAY: California health department warns of death cap mushrooms outbreak