Poisonous Mushrooms: What You Need To Know

Certain mushroom species found growing on the forest floor can be highly toxic and even deadly. Their names alone — death cap, funeral bell and destroying angel — drive that point home.

But mushrooms can also be extremely yummy, which explains why foragers pluck them for use in the kitchen.

So, how can you tell the difference between poisonous mushrooms and edible mushrooms? And what happens if you make a mistake? Let’s find out from wilderness medicine specialist Christopher Bazzoli, MD.

How to tell if a wild mushroom is poisonous

Poisonous mushrooms can look like edible ones. There’s no quick and easy way to tell one from the other — which is a problem. (Unfortunately, Mother Nature did not imprint a skull and crossbones symbol on deadly choices.)

“It takes a skilled mushroom hunter to identify what’s safe to eat and what’s not,” emphasizes Dr. Bazzoli. “This isn’t something where you can just use TikTok or an app on your phone.”

How confusing can it be? Consider the toxic Amanita phalloides — aka, the death cap mushroom. It’s a white toadstool with an umbrella-shaped top and is considered the world’s most poisonous mushroom.

Unfortunately, the death cap mushroom can easily be confused for Caesar’s mushroom, a gourmet delicacy among the fungi-eating crowd. It resembles several other tasty mushrooms, too.

“To the untrained eye, a poisonous mushroom can look pretty close to what you might find at the grocery store,” says Dr. Bazzoli. “The risks are high. That’s why you need to be very careful.”

Can poisonous mushrooms be deadly?

As the name suggests, eating a poisonous mushroom can have life-threatening consequences. Toxins in certain harmful mushrooms — like amatoxins in the death cap mushroom — can lead to fatal liver failure and kidney damage.

It’s estimated that more than 100 people die every year around the world after nibbling on the wrong fungi.

There’s no universal antidote for mushroom poisoning either. Treatment is typically limited to supportive care. A liver transplant may be an option in some cases.

Mushroom poisoning symptoms

Eating poisonous mushrooms typically brings on gastrointestinal discomfort within hours as your body reacts to the toxins. That can include unpleasant symptoms like:

• Nausea
• Vomiting
• Abdominal pain
• Diarrhea

While those initial symptoms may quickly improve or even disappear, that doesn’t mean the toxins are gone. Instead, they’ve entered a “latent phase” where they stealthily damage your liver and kidneys.

A day or so later, more serious and life-threatening symptoms may erupt. “That’s why it’s important to seek out emergency care immediately if you suspect you have eaten a poisonous mushroom,” urges Dr. Bazzoli.

Tips to avoid mushroom poisoning

Using caution is the #1 rule when it comes to eating mushrooms found in nature. “If you’re not absolutely sure that a mushroom is safe to eat, you’re better off leaving it alone,” recommends Dr. Bazzoli.

He also offers these tips to stay safe:

• Educate yourself. If you want to forage for mushrooms, learn how to do it from a seasoned mushroom hunter. Find a mushroom hunting group that offers expert-led hikes to find edible fungi.
• Respect regional differences. When traveling, don’t assume your local foraging knowledge applies elsewhere. Dr. Bazzoli says it’s not unusual for travelers to get sick eating poisonous mushrooms that look exactly like a safe mushroom from back home.
• Don’t expect to neutralize toxins. Cooking poisonous mushrooms won’t make them safe to eat because the toxins are heat-stable. Washing or soaking poisonous mushrooms also won’t eliminate the danger inside.
• Shop trusted sources. Only use mushrooms bought from grocery stores or other trustworthy vendors. Be wary of fungi sold at farmers’ markets or roadside stands. “You’re putting a lot of trust in whoever picked those mushrooms,” warns Dr. Bazzoli.

Only about 3% of mushroom species are poisonous, but they can be found virtually anywhere that mushrooms typically grow. The risk of that reality is summed up in this adage about foragers:

There are old mushroom hunters and bold mushroom hunters — but there are no old, bold mushroom hunters.

So, be smart and careful out there.