Fungi Fear Factor: The Hidden Dangers of Foraging for Mushrooms

You spot a cluster of mushrooms while hiking through the woods. They look just like the ones you’ve seen at the farmers market and, after a quick internet search, they seem safe to eat. But what you can’t tell from appearance alone is whether those mushrooms are harmless or among the most poisonous in North America.

Every year, roughly 7,400 people in the United States seek medical care after eating poisonous mushrooms. While many cases are mild, others can lead to severe illness, liver failure, or even death.

Mushrooms can be difficult to identify, even for people who have foraged before. Their appearance can change based on age, weather, soil conditions, and where they grow. Even mushrooms that look safe in a photo or field guide may have poisonous look-alikes growing nearby.

One of the best-known examples is the death cap mushroom, or Amanita phalloides. It is responsible for many fatal mushroom poisonings worldwide and can be mistaken for edible varieties.

Last year, Northern California experienced an unusually rainy season, leading to a boom in wild mushroom growth. Health officials documented 39 severe Amanita mushroom poisonings, including three liver transplants and four deaths, after people unknowingly ate toxic mushrooms they believed were safe.

“One of the reasons these poisonings happen is because people rely on appearance alone,” says Timothy Kolosionek, DO, second-year medical toxicology fellow with Lehigh Valley Health Network, part of Jefferson Health. “Unfortunately, appearance is not enough. Some of the most dangerous mushrooms in the world can look very similar to mushrooms people have eaten safely before.”

Many people have heard “rules” for identifying safe mushrooms. Unfortunately, none of these rules is reliable.

Don’t believe these common myths:

• MYTH: Cooking makes poisonous mushrooms safe.
• MYTH: Animals eating a mushroom means it is safe for people.
• MYTH: Poisonous mushrooms discolor silver utensils.
• MYTH: Safe mushrooms can always be identified by smell, color, or peeling the cap.
• MYTH: A mushroom identification app is enough to confirm whether something is edible.

In reality, many dangerous mushroom toxins are not destroyed by cooking, freezing, or drying. If a mushroom is poisonous in the woods, it can still be poisonous after it is prepared. “I’ve heard people say that boiling or cooking mushrooms removes the danger, but this is not true for many poisonous species,” Dr. Kolosionek says. “You can’t cook the risk out of a toxic mushroom.”

Symptoms depend on the type of mushroom, how much was eaten, and how quickly someone receives care. They may include:

• Nausea or vomiting
• Severe diarrhea
• Abdominal pain
• Confusion or hallucinations
• Excessive sweating or drooling
• Weakness or dizziness
• Liver or kidney damage

Some of the most dangerous mushrooms do not cause symptoms right away. With certain toxic mushrooms, symptoms may begin six hours or more after eating. A person may first develop stomach symptoms, start to feel better, and then become seriously ill as liver damage progresses.

That delay can make mushroom poisoning especially dangerous because people may assume they have a stomach bug or food poisoning and wait too long to seek care.

If you become sick after eating a wild mushroom, take it seriously:

• Call Poison Control at 1-800-222-1222 right away.
• Seek emergency medical care.
• Save leftover mushrooms, if available.
• Take clear photos of the mushrooms, including the cap, stem, underside, and where they were growing.
• Tell your care team when and where the mushrooms were collected and how they were prepared.
• Let your care team know if anyone else ate the same mushrooms.

This information can help medical toxicologists, emergency clinicians, and mushroom identification experts determine what you may have eaten and what treatment may be needed.

“If someone tells us they ate a wild mushroom, that information changes how we evaluate and treat them,” Dr. Kolosionek says. “Photos or leftover mushrooms can be very helpful, but the most important step is getting medical guidance quickly.”

The Northeast United States has many wild mushroom species, including some that are edible. But identifying them safely requires more than a quick search or casual experience. Commercial wild mushroom harvesters must meet specific qualification requirements before selling foraged mushrooms. This process underscores how specialized mushroom identification truly is.

For most people, the safest approach is simple: Enjoy wild mushrooms with your eyes, not your appetite. Take photos, learn about them, and appreciate them as part of nature. But when it comes to your next meal, stick with mushrooms purchased from a grocery store, a farmers market, or a reputable grower.

“Foraging can be a rewarding hobby if your goal is to observe nature,” Dr. Kolosionek says. “But if your goal is dinner, the safest choice is buying mushrooms from a trusted source. Free fungi can end up costing far more than they’re worth.”