‘Unprecedented’ spate of toxic mushroom illnesses jar California | California

A wet winter in California produced a surge of wild mushrooms – a mushroom boom that would generally have cheered foragers. But among the chanterelles and porcini mushrooms, a much more dangerous fungus called death cap – also known as Amanita phalloides – is causing concern.

The state health department reports that between late November 2025 and early February 2026, there were four deaths and 40 hospitalizations linked to the consumption of dangerous mushrooms, an outbreak the department calls “unprecedented.” That’s well above the state average, which typically sees fewer than five cases of mushroom poisoning per year.

Those who fell ill include a couple of seasonal farm workers from Oaxaca, Mexico, and ranged in age from 19 months to 67 years, according to the Associated Press. Many people have needed a liver transplant.

Rudy Diaz, resident mycologist at the Los Angeles Mycological Society, said these diseases have put the public on alert. Last month, while he was out with a friend looking at trailside mushrooms, a stranger chastised him for doing something “risky,” telling him he should know that people had recently been poisoned by mushrooms.

Although novice mushroom pickers may have difficulty identifying species, among knowledgeable mushroom enthusiasts there is no sense of panic, Diaz says. In Southern California, finding mushrooms requires keen eyesight and some understanding of the terrain. So the people who look for them tend to be better trained – which is why he thinks there are fewer cases of poisoning. “Those who discover mushrooms already have some knowledge of the local ecology,” he said.

It is nevertheless important that the general public becomes aware of this. People should always be very careful when picking mushrooms they intend to consume, says Jess Starwood, an herbalist, forager and educator who teaches about the wild plants of Southern California and Arizona. “As more people become familiar with mushrooms through media and popular culture, mushrooms are no longer feared,” she says – which brings challenges and benefits.

The mushrooms resemble other varieties of common mushrooms such as puffballs. They typically measure up to 6 inches in diameter and 6 inches in height and have a greenish-gray cap and white gills. “Death cap mushrooms can look a lot like edible species in the same family, and novice foragers can get it very wrong,” Starwood adds. “In the past, these deadly mushrooms were not as common as they are today, which increases the risk of misidentification.”

Eating half a capful or less could be enough to kill a person, with the mortality rate after ingestion reaching up to 50%. Dog owners should also watch out for fungi, she adds, as they are deadly to dogs as well.

The epicenter of the first 35 incidents was the city of Salinas on California’s central coast, which has a large population originally from central Mexico, where there is a strong mushroom-picking culture. Diaz speculates that people probably confused the deathcap with one of the edible Amanita species they were familiar with in their home countries. While many residents speak Spanish, the epidemic has also affected people speaking English, Mandarin, Mixtec, Russian and Ukrainian. As a result, the state Department of Public Health released a new flyer containing QR codes sharing the poisonous mushroom advisory in nine languages.

Climate change also makes it more likely that lesser-known mushroom species will appear in places where they are rarely seen. Wet winters mean a lot more fungi, and often atypical species appear in areas where they hadn’t appeared before, Starwood says. This could mean death caps appearing in new areas where other edible mushrooms have been harvested for years. The Western destroying angel mushroom (Amanita ocreata) is also very toxic and common in coastal areas of California through April.

Deathcap season is now over in Southern California, but it continues in Northern California. Experts advise inexperienced mushroom hunters to seek out a local mycological society or foraging group to learn directly from experienced local experts how to eat wild mushrooms safely.

“It took me several years to become familiar with the edible California Amanita species before I had the confidence to eat them,” Diaz said.

The national health agency also advises people to only buy mushrooms from trusted grocery stores. Death cap mushrooms are still toxic even after cooking, boiling, freezing or drying. They also say to seek help immediately if anyone suspects poisoning. Symptoms may include stomach pain, cramps, fatigue, nausea and diarrhea. More serious liver damage occurs within a few days.

Starwood adds that relying on an app can be dangerous because it is known to make errors. “Using an experienced guide who can teach in the field is the best resource,” she says. “If you’re not sure, don’t eat it.”