Most Dangerous Mushrooms

Wild mushrooms generally fall into four categories: Edible, inedible, poisonous, and downright deadly. Foraging for fungi is fun. But you should know how to spot a toxic mushrooms.   

You certainly don’t have to be a mycologist to know the safe ones from the deadly ones. With this guide, you can avoid poisonous mushrooms so that you can focus on the edible species.  

Here are the most dangerous mushrooms in North America: 

Death cap mushroom 

The mortality rate for consuming a death cap—scientific name Amanita phalloides—is between 10% and 30%. It is responsible for 90% of all mushroom-related deaths. It is probably what was used to kill the Roman Emperor Claudius. This makes it the world’s most deadly mushroom. 

They look like most white mushrooms: yellowish with a smooth cap and white gills, the kind you’d find in a grocery store. The only place they grow naturally in the Southwest is California.   

Once you consume one, there is no going back because there are no antidotes. The first 6 to 24 hours after consumption, you won’t have symptoms, but the toxins will be damaging your liver. Then, you will have gastrointestinal symptoms like abdominal pain, diarrhea, and vomiting. The worst part of death cap mushroom poisoning then occurs: It appears like you’re improving. In reality, you’re going through the double whammy of  kidney failure and liver failure.  

Destroying Angel 

A perfect name for an incredibly deadly mushroom. The ‘angel’ aspect comes from its pristine white beauty. The ‘destroying’ part comes from its amatoxins, which can cause multi-organ failure that can lead to death in three to five days.   

It grows in woods and grasslands, sprouting in late summer and autumn. A destroying angel looks like button mushrooms and puffballs. Novice foragers often pick them without realizing it.   

Describing them isn’t helpful, given that they look like any white mushroom you’d buy in the supermarket. The cap is smooth; the gills are white. The stem is skinny. Its smell does not indicate its danger, giving off a mild, slightly sweet odor.  

The best thing to do is either not eat wild mushrooms or be well-versed in mushroom species so you can tell which are which.  

Galerina marginata 

It’s colloquially known as funeral bell, deadly skullcap, autumn skullcap, or deadly galerina.   

Symptoms follow the same course as all toxic mushrooms: No immediate symptoms for 6 to 12 hours, painful GI problems for roughly a day, the appearance of recovery, then organ failure, and central nervous system damage over 3 to 7 days.  

These are easier to spot than other deadly mushrooms. Their caps are brownish-yellow and smooth. They usually grow on decaying wood from summer to late autumn.   

Eating one requires immediate hospitalization. 

False Morel 

Gold has fool’s gold, and morels have false morels.   

Morels are some of the most famous mushrooms to forage for. Their honeycomb-like cap is famous and makes them easy to spot, given how different they are from other fungi.   

Unfortunately, false morels also exist. They contain a toxic substance called gyromitrin, which the human body naturally converts to the even scarier-sounding monomethylhydrazine—the same chemical used in rocket fuel. But instead of shooting you into space, this substance will launch you into an early grave.  

The good news is that it’s pretty easy to tell them apart. Fake morels are wrinkled with a brain-like appearance; real morels are pitted like a honeycomb. It’s reddish-brown; real morels are yellow or black.   

The easiest difference to spot is the interior: The inside of a real morel is hollow, while the false ones are solid. 

Fly Agaric 

This mushroom is straight out of a fairy tale. The amanita muscaria has a bright red cap with white spots. Despite its magical appearance, it is not something you should eat.  

The toxicity is high, with neurotoxins that can cause a range of effects, from hallucinations to comas and death—the fly agaric features in various folklore and fairy tales.   

They grow in northern temperate forests and should be admired for their beauty but never eaten. 

Deadly Webcap 

This is perhaps the deadliest of all the poisonous fungi in the world. It looks boring—a brown cap, earthy smell, and yellowish stem. It grows in coniferous forests around pine and spruce trees.   

It has a toxin called orellanine, which causes kidney failure. There is no antidote, so the best course of action is getting treatment immediately. Early symptoms are chills, nausea, headaches, and muscle aches.   

In the late stages, your kidneys will shut down, possibly requiring lifelong dialysis or a transplant. 

Other species to avoid 

Here are some more toadstools to watch out for: 

• Jack o’Lantern (Omphalotus illudens) – Bright orange and often confused with chanterelles, it causes severe gastrointestinal distress. 

• Fool’s Webcap – A common name for C. orellanus, its harmless appearance makes it especially deceptive and dangerous. 

• Dapperling (Lepiota spp.) – Some small dapperling mushrooms, especially in the Lepiota genus, are lethal due to amatoxins. 

• Conocybe filaris – Found in lawns and woodchips, this unassuming brown mushroom contains deadly amatoxins. 

• Amanita bisporigera – Commonly found in eastern North America, especially in wooded areas of the United States and Canada. Often mistaken for edible mushrooms. 

As a general rule of thumb, if you aren’t 100% sure, leave it in the forest. Mushroom foraging is fun, but you should be very educated on what you’re picking.