Marin vets warn toxic mushrooms are sickening dogs across the Bay Area
More than 10 suspected dog poisonings hit one Marin emergency center in three weeks, as death caps and other toxic Amanitas spread through wet Bay Area yards and parks.
Marin veterinarians have seen a sharp rise in dogs sickened by suspected mushroom poisonings, with the Pet Emergency and Specialty Center of Marin treating more than 10 cases in a three-week stretch. The spike has turned ordinary places like yards, park edges and neighborhood greenspaces into risk zones whenever rain pushes mushrooms up fast.
The warning matters because the dangerous local species are easy to miss in the field. Marin Humane has singled out the death cap, Amanita phalloides, and destroying angel, Amanita ocreata, as the most dangerous mushrooms for dogs and people in Marin. Death caps can show up white, yellow, green or brown, and often carry a white ring or skirt on the stem with a sac-like cup at the base, the kind of traits foragers learn to watch for in Amanita.
These mushrooms tend to appear after rainfall and under or near trees, especially oaks, which puts them squarely in the same suburban habitats where dogs sniff, wander and sometimes grab a bite off the ground. That overlap is what makes Bay Area mushroom season tricky: the same wet weather that brings out edible fruiting bodies also favors lethal Amanitas in the middle of shared outdoor spaces.
The dog cases came against a wider California outbreak of amatoxin poisonings. The California Department of Public Health said the 2025-2026 season produced severe liver damage, three adult fatalities and three liver transplants, far above a typical year with fewer than five amatoxin cases. San Francisco public health later said California had logged 40 cases between Nov. 18, 2025, and Feb. 9, 2026, with four deaths and three liver transplants. UCSF Pharmacy said early seasonal rains created ideal conditions for toxic mushroom growth in the Bay Area and Monterey County.
For anyone foraging, walking a dog or letting a pet roam after rain, the lesson is simple: a mushroom patch in a yard, trail or park is not harmless just because it is common. When more than 10 suspected cases can land in one Marin clinic in three weeks, the safest move is to treat wet ground as a place to look twice before a dog looks first.
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