What Makes Death Cap Mushrooms the Deadliest in the World?

Key Takeaways About the World’s Deadliest Mushroom:

• Death cap mushrooms are considered the deadliest in the world. They make up about 90 percent of mushroom poisoning deaths each year.

• Consuming any part of the death cap mushroom, including the cap and stem, will lead to kidney and liver failure. You can only die from the death cap mushroom by eating it, touching it will not harm you.

• Death cap mushrooms are native to Europe but were mistakenly introduced to Australia and California.

In 2023, Erin Patterson of Leongatha, Australia, murdered three and critically injured one member of her family using a deadly mushroom. The day seemed innocent enough, a lunch of beef Wellingtons and conversation amongst family, with Patterson and her in-laws.

But the lunch turned deadly because Patterson had included the world’s most poisonous mushroom: the death cap, into the meal. In no time, every guest had to be hospitalized, and three would die of liver failure within the week.

Death cap mushrooms, also known as Amanita phalloides, are among the deadliest mushrooms in the world, and while there are many lethal mushrooms, this is the most frequently consumed, causing the most injury. Annually, around 100 people die of mushroom poisoning, and 90 percent of them die from the death cap.

The mushrooms are part of a deadly clade called Amanita. These potent killers contain poison that remains stable whether heated or frozen. This means that you could freeze them for a month and then cook them, and they would still be deadly. If you sauté them, as Patterson did, they can still kill. What’s more, every part of the death cap mushroom is toxic, from the cap to the stem.

Read More: After Thousands of Years, Humans Are Still Finding New Uses For Mushrooms

How the Death Cap Mushroom Kills

You have to consume the mushroom in order for it to be deadly. Touching the mushrooms isn’t enough for them to make you sick. Matthew Smith, a professor in the Department of Plant Pathology at the University of Florida and curator of the Fungal Collection (Fungarium) of the Florida Museum of Natural History, says that he handles the mushrooms in order to take pictures of them.

“They’re like paint, you can touch them and get them on your hands, but you wouldn’t eat them,” says Smith.

The death cap kills by hindering protein and MRNA synthesis, leading to cell death in the liver and the kidneys. Eventually, individuals die of liver and kidney damage. Although several treatments are available, none are effective enough. Outcomes largely depend on how much is consumed, how quickly it’s diagnosed, the size of the person, and their age, says Smith.

“Sometimes people get off lucky with liver damage,” says Smith. Other times, liver damage is so severe that they have to get on dialysis, a treatment that removes waste from the body when the kidneys no longer function properly. If the damage is bad enough and they don’t get treatment in time, many will fall victim to the death cap.

Where Death Caps Live and How to Avoid Them

Amanita mushrooms, of which death caps are one group, have a symbiotic relationship with plants, mostly trees. These mushrooms aren’t cultivated, and while they could perhaps survive in your yard if you have ample trees, they would most likely be found in the woods.

The mushrooms often grow on oak or pine trees. They’re large and grey and could be confused with an edible species for those who aren’t careful, and while it’s a European species, it’s also invasive and has been accidentally introduced to California and Australia, where Patterson was charged as the “mushroom murderer.”

The tricky aspect of death caps is that they smell desirable, and for those who have survived eating them, they also taste good. While many deadly mushrooms aren’t appealing, this group would be tasty if it weren’t so deadly.

It’s also true that pets can die from death caps. Smith, who also works with poison control in Gainesville, Florida, says that both human and veterinary calls come into the center. If you’re walking your dogs, know that poisonous mushrooms can kill them, too.

“If you’re gonna hunt for mushrooms out in the woods or in any kind of natural environment, you really need to know what you’re doing,” says Smith.

Read More: Undisclosed Synthetic Psychedelics Found in Magic Mushroom Edibles Instead of Psilocybin

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• BBC. Erin Patterson found guilty of murdering relatives with toxic mushroom lunch

• Woodland Trust. Death Cap (Amanita phalloides)

• CCDC Weekly. Preplanned Studies: Mushroom Poisoning Outbreaks — China, 2019

• North Carolina State Extension. Amanita virosa