Most Poisonous Mushrooms

Everybody knows that for most of us going into the woods to pick and eat a random selection of toadstools and mushrooms is pretty much like playing Russian roulette – it’s been drummed into us since we were reading fairy tales. The point is unless you are an absolute expert on gathering mushrooms you should probably steer well clear. But, I hear you say, isn’t it the red ones with white spots to watch out for?! Well that’s one type to avoid, and they will make you pretty ill. The one’s that will really do some damage look pretty unthreatening, often just like the edible ones.

One estimate I read puts the number of cases of mushroom poisonings at between 6-7,000 cases a year in the USA alone. Whilst the fatality rate is a fraction of a percent many do experience serious poisoning symptoms. Many of these cases are children but there are plenty involving adults, and in extreme cases entire families have been poisoned.

In total there are about 30 species of mushroom that have proven consistently fatal to humans, many of which are related. In addition there are a further 20 that have on occasions been known to cause death. The list below includes those responsible for killing the most people or with the greatest potential to do harm.

10. Fly Agaric (Amanita muscaria)

Fly agaric - Amanita muscaria

Photo: H. Krisp / License

The fly agaric is the iconic toadstool of children’s fairy tales. Instantly recognisable with its bright red cap and white spots you would have to be an idiot to eat one of these! Or a child or pet. Whilst you can imagine why a kid may eat one of these it is less clear why dogs (and occasionally cats) seem to have a taste for them. Unfortunately fly agaric is even more poisonous to these animals and invariably lethal.

The main toxic agents in Amanita muscaria are muscimol and ibotenic acid. These act on the central nervous system causing loss of coordination, alternating agitation and sleep, nausea and in some cases hallucinations. The effects kick in after around one hour but are rarely fatal. One of the biggest risks is due to the crazy behaviour exhibited when intoxicated. Something that didn’t escape the ancients who used these in rituals.

9. Angel Wing (Pleurocybella porrigens)

Angel wing - Pleurocybella porrigens

Found throughout the Northern Hemisphere angel wing gets its name firstly from how it looks and secondly because eating it gives a good chance of sending you heaven-bound.

The angel wing was at one time considered edible and it seems that for many years there were no reported poisonings from eating it. That changed in 2004 when nearly 60 people became ill after eating them across Japan. Out of these 17 died during the following six weeks.
In a further case in 2009 a 65-year-old man died of encephalopathy (brain disease) after eating angel wings. It is worth pointing out that many of those who died had pre-existing kidney or liver problems.

The mode of toxicity isn’t well understood in this fungus but a unique amino acid has been identified that kills the brain cells of lab animals. It is also possible that the fungus contains elevated levels of cyanide.

8. Deadly Dapperling (Lepiota sp. )

Deadly dapperling - Lepiota

The name is a bit of a give away with this one. This small, tasty looking mushroom and many of the Lepiota family, contain the deadly amatoxin which is capable of destroying the liver. It is this toxin that is responsible for 80-90% of all mushroom poisoning deaths. The fatality rate from ingesting amatoxins is around 50% if untreated and still 10% with treatment. The initial symptoms are gastrointestinal-intestinal distress but death may take some time and result from liver failure.

It is found in conifer forests throughout Europe and North America and has been responsible for several deaths over the years.
Other members of the family include the equally delicious sounding deadly parasol.

7. Podostroma Cornu-damae

Podostroma cornu-damae

Photo: Kouchan / License

These funky looking Japanese fungi shout “Don’t eat me”! Well to me anyway. Obviously not to the folk of Japan though. I suppose they are already slightly fatalistic about their food, expecting to die every time they have a bit of puffer fish. Apparently this fungus looks like young Ganoderma lucidum and is only eaten in error though.

The main toxins in these fungi are trichothecene mycotoxins which have particularly unpleasant effects and may cause death within a matter of days. The symptoms are system wide and can affect all organs, primarily liver, kidneys and brain. There is also a depletion of blood cells, peeling of skin off the face and hair loss making it look like the victim is suffering from radiation poisoning (or leukemia).

6. Conocybe Filaris

Conocybe filaris

Photo: 414n / License

This mushroom is commonly found on lawns and is native to the Pacific Northwest region of the US. Whilst it doesn’t look immediately inviting as a snack its appearance in gardens brings it into closer proximity with people than many other mushrooms.

The other factor in accidental poisoning with this mushroom is the alleged similar appearance to the Psilocybes mushroom, also known as magic mushrooms. However, taking one of these could lead to the mother of all bad trips.

This fungus is known to contain the particularly deadly amatoxin which if ingested can cause irreparable liver damage.