Following the hospitalization last month of a Bellevue woman who ate a poisonous mushroom, King County health officials are warning people foraging for mushrooms to exercise caution.

The woman apparently picked at ate a species known as Amanita Phalloides, or “death cap” mushroom, a highly toxic mushroom that cannot be distinguished from safe mushrooms by taste or smell.

“It takes extensive knowledge to know which mushrooms are safe to eat and which are poisonous,” said Dr. David Fleming, Director and Health Officer for Public Health – Seattle & King County. “Amanita phalloides look very much like some edible types of mushrooms and increasingly can be found in the wild, in local parks, and even in our own backyards. Only people who really know what they’re doing should eat mushrooms they’ve picked themselves.”

Symptoms of poisoning by these mushrooms include abdominal pain, vomiting and diarrhea. The first symptoms usually start within six to 24 hours of ingestion. Poisoning may result in damage to the liver and other vital organs, or even death.

Although cases of poisoning from Amanita phalloides have been reported in Portland and British Columbia, the poisonous mushrooms were thought to be rare in Washington state until recently. There have been increasing numbers of the mushrooms spotted this fall, perhaps due to the wet weather.

“Mushroom poisonings are almost always caused by people eating wild mushrooms collected by nonspecialists,” said Dr. William Hurley, Medical Director for Washington Poison Center. “People hunting for wild mushrooms – especially novices – might misidentify a toxic species. Or recent immigrants might mistake a poisonous mushroom for an edible mushroom from their native land. In fact, the reported cases of poisoning by Amanita phalloides in the Northwest have been immigrants from Thailand, Cambodia and Laos.”

The Puget Sound Mycological Society offers mushroom identification clinics for the public on Mondays from 4-7 p.m. at the University of Washington’s Center for Urban Horticulture through the end of October. Visit www.psms.org or call 206-522-6031 for more information.

If you suspect you may have eaten a poisonous mushroom, do not wait for symptoms to appear. Call the Washington Poison Center at 1-800-222-1222 right away.