After a recent fatal poisoning, health experts say one truth stands out: if you're not absolutely sure about a wild mushroom, don't eat it.
The California Department of Public Health (CDPH) issued an urgent advisory following a recent outbreak of amatoxin poisoning linked to the consumption of wild, foraged mushrooms. One person has died and hospitals throughout the region have seen a rise in hospitalizations after people have eaten dangerous poisonous mushrooms.
Since Aug. 1, the California Poison Control System in Sacramento has received 358 mushroom ingestion cases with 204 people needing medical evaluation.
"Identifying mushrooms is challenging, and many cases of ingestion require hospital evaluation," shared Justin C. Lewis, director and clinical toxicologist for the California Poison Control System in Sacramento.
"While most recent exposures have occurred in the Bay Area, we've historically seen cyclopeptide mushroom poisoning outbreaks across Central and Northern California. That means there's still a real risk in our local region," added Lewis, an assistant clinical professor at the UC Davis School of Medicine.
To better understand the risk of eating wild mushrooms, we consulted with James Chenoweth, a medical toxicologist in the Department of Emergency Medicine at UC Davis Health. He answered common questions about why we are seeing more cases, what symptoms people should watch for and what to do if you or someone you know eats a wild, poisonous mushroom by mistake.
What makes some wild mushrooms dangerous to eat?
Certain mushrooms can cause severe harm. Some species damage the liver, others affect the kidneys and one type can even trigger seizures. Most of the mushrooms that people find in their yards only cause mild symptoms like nausea, vomiting and sometimes diarrhea, which usually resolve quickly. However, dangerous varieties like Amanita phalloides — also known as the death cap — can cause life-threatening liver failure and may require a transplant.
Why are poisonings from wild mushrooms on the rise?
This year's weather created ideal conditions for Amanita mushrooms to thrive. Experts at the poison center say it's similar to 2016, when a favorable growing season led to a spike in poisonings. These mushrooms sprouted abundantly, and many people accidentally picked them while looking for edible varieties.
"The number one rule is simple: If you're not sure, don't eat it. This is especially true for wild mushrooms."-James Chenoweth
How can someone tell if a mushroom is poisonous?
The number one rule is simple: If you're not sure, don't eat it. This is especially true for wild mushrooms. The deadly Amanita phalloides is usually white and has distinct features like a partial veil. Early on, it can resemble edible button mushrooms used in some Asian dishes, which is one of the varieties people mistake them for. As they grow, they become easier to identify.
Some mushrooms, like boletes or chanterelles, are easier to recognize and don't look like poisonous varieties. Others, such as morels, have toxic look-alikes like the false morel. Misidentification is more common with certain white mushrooms or when people hunting for mushrooms, known as foragers, come from regions where similar-looking mushrooms are safe to eat. When in doubt, don't take the chance.
What symptoms should people watch for after eating a wild mushroom?
One of the most concerning signs is delayed symptoms. Less toxic mushrooms usually cause nausea and vomiting within the first six hours. In contrast, Amanita phalloides classically causes nausea and vomiting more than six hours after ingestion. That delay is a red flag for toxicologists because it suggests the person may have eaten one of the most dangerous species.
How do you treat someone with mushroom poisoning?
Unfortunately, there's no simple antidote like we have for some other poisonings. Treatment is mostly supportive — IV fluids, critical care and sometimes liver transplant. There are experimental options, such as silibinin (a milk thistle extract) and high-dose penicillin, which aims to block amatoxin absorption and protect the liver. N-acetylcysteine, an antidote used for acetaminophen overdose, is also often given to patients with evidence of liver injury. But these are not guaranteed cures, so early medical care is essential.
What should you do if you or someone you know eats a wild mushroom by mistake?
If you're concerned, call the Poison Center at (800) 222-1222 right away or go to your local emergency department. Doctors can work with the poison center to identify the mushroom and advise on what symptoms to watch for. If there's a high risk of a toxic species, treatment may include activated charcoal to help reduce absorption of amatoxins.
