Which Mushrooms Are Poisonous

Looking to expand your wild mushroom foraging? Wild mushrooms can be tasty and delicious and free. A great fall weekend usually involves some mushroom hunting. Poisonous fungi can be quite deadly though. In this article we’ll cover which mushrooms are poisonous, at least the most common ones out there.

Safety Note – Wild mushroom poisoning is a serious issue. The worst of them almost guarantee death unless you can get a liver transplant. This article is for educational purposes only. Ideally you’ll learn about mushrooms in the field with a professional. Never ever eat a mushroom you haven’t positively identified and never eat one out of season.

Death Cap Mushrooms

First up we have the Death Cap mushroom (Amanita phalloides). This wild mushroom is most commonly found in Europe in the summer and early fall. It’s also one of the most deadly mushrooms around.

It has a large white cap and stem. It’s one of the many white mushrooms to avoid in the wild. The caps of phalloides can also be slightly greenish.

Death Cap mushroom (Amanita phalloides)

Other Deadly Amanita Mushrooms

In general Amanita mushrooms look similar and many of them are deadly via amatoxin. If you see a light colored mushroom (white, grey, or slightly green) that fits the standard toadstool shape then absolutely double check that you know what it is.

One of the more common deadly Amanitas is the “Destroying Angel”. In the Eastern US it’s Amanita bisporigera, in the western US it’s Amanita ocreata, and in Europe it’s Amanita virosa.

Unlike the death cap, Destroying Angel Amanitas are all white. There’s not green or blue tinge to the top cap.

Few edible species look like Amanitas and it’s best to stay away from any that do.

The Standard Shape of the Amanita Family

Fly Agaric

Fly Agaric (Amanita muscaria) is hallucinogenic. In a way it’s poisonous but not in the deadly way that it’s Amanita cousins are.

It can be found in higher elevations throughout the northern hemisphere. It’s even been accidentally introduced to the south via pine and birch plantations.

Still, be very wary of this mushroom. You may think you’ve found a hallucinogenic jackpot only to stumble upon one of it’s deadly cousins in or out of season.

Fly Agaric (Amanita Muscaria)

Psilocybin Mushrooms

There are many species of psilocybin mushrooms (aka magic mushrooms). Their poisonous function isn’t deadly, it’s hallucinogenic.

The main danger with Psilocybe mushrooms is confusing it with other Little Brown Mushrooms, commonly known as LBMs. Of that style there are many that are poisonous and some that are deadly poisonous.

If you’re trying to avoid poisonous LBMs get to know how to do a spore print. Plus check out all the LBM look alikes. Or just avoid this group altogether. With any luck it won’t be a felony forever!

False Morel

We cover false morels in another article. Their edibility versus poisonous nature is debated. If you hunt morels you need to understand the risks and how to identify them as there are several species of false morels.

The caps of true morels attach to the stem as shown in the picture below. Morels also appear in the spring, not the fall. They prefer areas that underwent a forest fire within the last few years.

False morels have a separate cap. Overall there are 4 types of false morels. Get to know them all at our article on the best places to find morels. Study the false morel section at the end.

Morels showing hollow stems and caps attached to stem at base of caps
Morels showing hollow stems and caps attached to stem at base of caps Image by Alan Stanley from Pixabay

Inky Cap

Inky cap mushrooms (Coprinopsis atramentaria) aren’t specifically poisonous. They do interact with alcohol consumption. Even having alcohol a few days after eating inky caps can lead to problems.

According to the book, Mushrooms: poisons and panaceas—a handbook for naturalists, mycologists and physicians, symptoms can include nausea, vomiting, agitation, reddening face, or tingling in the limbs.

Deadly Webcap

The deadly webcap (Cortinarius rubellus) grows in North America and Europe. It’s highly poisonous. Eating it could lead to kidney failure. Beware the Cortinarius. It’s not to be messed with.

This genus lies within the Orellani of the family Cortinariaceae. These mushrooms contain orellanin, the cause of kidney failure due to eating deadly webcaps. Note that symptoms are delayed a few days after eating.

Deadly webcaps are brown and have a classic toadstool shape. Caps are 1 to 3 inches in diameter with gills underneath.

Lepiota

Lepiota is a genus of white toadstool shaped field mushrooms similar in appearance to the Amanitas. Not all are poisonous but some area deathly poisonous.

Stems are slender and tall and caps are usually small, less than 4 inches in diameter with gills underneath.

Example Green-Spored Lepiota

Clitocybe

Clitocybe is a thick stemmed, small capped genus of mushrooms. Most are white or light colored. Again, not all are poisonous. The ones that are poisonous are very difficult to tell apart from their non-poisonous kin. Expertise required and due to that few of these are ever picked for consumption.

Avoid them.

Clitocybe nebularis

How To Tell The Difference Between Poisonous And Edible Mushrooms

Guidelines For Toxic Mushroom Identification

  1. Never eat something you haven’t positively identified
  2. Never eat a mushroom out of season. You may end up eating a poisonous look alike instead.
  3. Take local courses in edible mushroom identification. Go out with a professional who’s been doing this for years.
  4. Learn the easy to identify edible mushrooms first. Some edibles like giant puffballs or chicken of the woods shelf fungus don’t have a lot of look a likes. Learn these first.
  5. Learn all the look a likes of local edible mushrooms.
  6. Do a spore print and compare that with a dichotomous key of mushrooms.
  7. Know the toadstool shape – flat top cap with gills or pores sitting on a stem.
  8. Avoid white, brown, or light colored toadstool mushrooms. Not all are poisonous but the super deadly ones are to be avoided at all costs.
  9. Know the end game of mushroom poisoning. For the worst, it’s death with delayed symptoms where it’s too late to do anything.
  10. Again, never eat a mushroom that you haven’t 100% identified.
  11. Grow your own from safe sources of spores and spawn!

Facts and Statistics on Mushroom Poisoning

According to the National Poison Data System (NPDS):

  • Over 133,000 people called about eating potentially poisonous mushrooms between 2000 and 2018 (1).
  • Of the 133,000 cases over the last 18 years, over 700 resulted in major harm (1).
  • Of the 704 cases involving major harm, 52 resulted in death (1).
  • There are over 5,000 species of mushrooms worldwide (2).
  • 3% of named mushroom species are poisonous (2).
  • Mortality rates for mushroom poisoning at hospitals ranged from 12% to 22% via several studies conducted at hospitals in the middle east (2).
  • The average time to death from mushroom poisoning varies between 1 and 10 days (3).
  • Death from amanita poisoning usually happens within 1 to 3 days from liver failure (3).
  • A California study found the death rate from Amanita poisoning to be 10% (4).

Sources:

  1. https://pubmed.ncbi.nlm.nih.gov/30062915/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2882543/
  3. https://en.wikipedia.org/wiki/Mushroom_poisoning
  4. https://www.cdc.gov/mmwr/volumes/66/wr/mm6621a1.htm

Effects Of Poisonous Mushrooms

The most drastic effect of mushroom poisoning is death. This is usually cased by liver failure (Amanita poisoning – e.g. Amanita phalloides or amatoxin) or kidney failure (Orellani poisoning).

Negative symptoms are often delayed by 24 hours or longer. This makes treatment difficult. However, from the hospital studies referenced above, death rates range from 10 to 20% for those that go to the hospital quickly after ingesting mushrooms.

Signs Of Mushroom Poisoning

Initial signs of mushroom poisoning vary widely depending on which mushroom you ate and how much you ate. See wikipedia’s mushroom poisoning page for a detailed chart of symptoms sorted by mushroom.

Note – If you think you have eaten poisonous mushrooms go to the emergency room immediately. Do not wait for symptoms. Also, call the Poison Control Center at (800) 222-1222. Again, do not wait. The faster you get treatment the higher the chance or survival.

General symptoms are as follows for some of the most common poisonous mushrooms.

Amanita Poisoning Symptoms (Amatoxin)

Primary poison – Alpha-amanitin

  1. 6 to 24 hours – no symptoms
  2. Gastrointestinal discomfort, vomiting, lots of watery diarrhea
  3. After 24 hours up to 3 days – Extreme liver damage
  4. Liver Failure
  5. Death – Mortality rate is 10 to 15 percent

Deadly Webcap or Orellani Mushroom Symptoms via the Poison Orellanin

Primary poison – Orellanine

  1. No symptoms for 3 to 20 days
  2. Kidney failure begins midway through
  3. Kidney pain, thirst, vomiting, tiredness, headaches

Treatment For Mushroom Poisoning

Note – If you think you have eaten poisonous mushrooms go to the emergency room immediately. Do not wait for symptoms. Also, call the Poison Control Center at (800) 222-1222. Again, do not wait. The faster you get treatment the higher the chance or survival. There are no silver bullet antidotes

Also, note that this is form informational purposes only. It comes from the Journal of American Board of Family Practitioners (source).

Treatment for Cyclopeptide (Amanita or LBM poisoning via amanitin and amatoxins)

  1. Use activated charcoal to reduce absorption
  2. Add fluids to increase urine output
  3. Monitor input and output of fluids
  4. Tests will be conducted for the following: liver panel, blood glucose, blood urea nitrogen, and others
  5. To support the liver doctors use the following: lactulose, neomycin, vitamin K, lowering protein in the diet, thiamine
    1. Liver conditions are monitored and in extreme cases liver transplants are required
  6. To support a failing kidney doctors do the following: Add fluids, furosemide, dialysis, silibinin and penicillin

The article also includes instructions on dealing with hallucinogenic mushroom poisoning, false morel poisoning, and other forms of stomach upset from mushrooms.

Using An Online Mushroom Guide

Apps for identifying mushrooms in the field

Android Mushroom Apps

iOS Mushroom Apps

Websites for Identifying Mushrooms