False Morel

Safety first. The false morel (Gyromitra esculenta) is a poisonous mushroom, even though it is eaten in some places after special preparation. Its toxin, gyromitrin, is changed in the body into a hydrazine that can harm the stomach and gut, the liver and the nervous system. [5] [7] In published case reports, stomach symptoms usually came first and were often delayed, with a median onset of about 9 hours, followed in some people by liver and nerve effects. [3] If anyone may have eaten a false morel, or any wild mushroom you cannot be sure about, call Poison Help now at 1-800-222-1222 (US) and do not wait for symptoms. [1] [2] In other countries call the local poison centre or emergency number. Call 911 (or your local emergency number) for collapse, a seizure, trouble breathing or if the person cannot be woken. See Mushroom Poisoning: Symptoms and Urgent Help.

This page is a safety profile. It does not help anyone identify a wild mushroom. Do not identify wild mushrooms from text, photos or apps; even very experienced gatherers can find it hard to decide whether a mushroom is safe. [1] It is not psychoactive and has no proven health use.

What it is

Gyromitra esculenta is the species usually meant by "false morel" (also called lorchel or beefsteak morel). [7] The name "false morel" is also applied to other fungi that contain similar toxins, such as Gyromitra relatives and Verpa bohemica. [7] [5] Do not mix it up with the true morels (Morchella), which are a different genus; read Morel for how true morels are cooked and what poison-centre studies found. The two are confused in published poisoning reports: resemblance between "true and false morels" has led to Gyromitra being eaten as if it were Morchella. [4] That sentence is about reports, not a way to tell them apart.

The toxin and how it acts

• Gyromitrin is a small hydrazine-type compound. It is volatile and dissolves in water. [7]
• In the stomach it is split into N-methyl-N-formylhydrazine and then monomethylhydrazine (MMH), the compound mostly held responsible for the acute poisoning. [6] [7] The conversion depends on stomach acidity and is not complete. [7]
• MMH ties up vitamin B6 in its active form. That form is needed to make GABA, a calming signal in the brain, so less GABA can lead to the nerve effects and seizures seen in severe cases. [5] [7]
• The exact mechanism of toxicity is not fully known. Other effects described in the lab and animal literature include liver cell damage and cancer-causing potential of MMH in animals. [7] [8]
• Poisoning can also happen from breathing the vapours released while the mushroom is cooked. [8] [7]

What the reports show: symptom timeline

How to read this: the published case reports lean towards serious cases, so the death rate in them probably overstates the risk for everyone who eats it. The Michigan series, which counted every case reported to one poison centre, had no deaths. [3] [4] Reactions differ between people and between mushroom collections, and researchers have linked this to differences in dose, in the mushroom, and in people's own genetics. [4] [5] A reaction can start with a stomach upset that seems to pass; do not take that as a sign of safety. [1]

Treatment as described by authoritative sources

There is no home remedy and you should not try to treat this yourself. The poison centre will tell you what to do. Treatment is mostly supportive hospital care (fluids, monitoring and liver checks). [4] [8] Reviews describe vitamin B6 (pyridoxine) given by a hospital as an antidote for severe nerve effects, benzodiazepines for seizures, and liver transplant in the most severe liver failure. [8] [7] In the Michigan series pyridoxine was used in 7 of 83 symptomatic people, those with liver or nerve effects. [4] Doses are for clinicians and are not given here. The evidence for some other treatments mentioned in reviews, such as folinic acid and N-acetylcysteine, comes from case reports, and controlled studies are lacking. [7]

Cooking, drying and special preparation

• Eaten in some places. The false morel is sold and eaten in some Scandinavian countries after parboiling, and the habit continues partly because people believe the toxin is removed. [5] A review says the processing was found inefficient, and still recommends that false morels be treated as inedible. [5]
• What the measurements show. Gyromitrin is volatile and water-soluble, so thorough boiling or long drying lowers it, but only partly. [7] One of the papers we read quotes older work in which air-drying for 3 months cut the hydrazine-releasing compounds by one third to two thirds, and in one study long air-drying left less than 3 mg/kg from 57 mg/kg. [6] That is a statement about laboratory content, not a cooking method, and we give no preparation instructions. Cooking vapour can itself poison. [8]
• Why this site does not teach preparation. General poison-centre advice is that cooking, canning, pickling, freezing and drying do not remove the toxins from poisonous mushrooms. [1] See Cooking Edible Mushrooms Safely for mushrooms that are safe to eat.

Possible long-term concern: ALS

Researchers who studied a cluster of sporadic motor neurone disease (ALS) in the French Alps proposed that Gyromitra eating might play a role in susceptible people. [5] [6] This is a hypothesis from a small number of cases and mushroom samples, not an established cause. We list it so you know the question exists; it is not a reason for fear or proof of harm.

Lab data and chemistry

This section reports what laboratories have measured in false morels. It is not a recipe and not a safe-level table. Wikidata (the open knowledge base behind the LOTUS project) lists 32 compound statements for Gyromitra esculenta, with no paper references attached in the file we received. [9] A listing means "reported in at least one study of this species", not "present in every mushroom".

A. What the laboratory literature reports in this mushroom

B. Measured values

C. What the numbers do and do not mean

• The two G. esculenta values differ about 2.7-fold, and these are single specimens, so no average can be drawn. Content differs with site, collection, species and handling. [6]


• Values are on dried weight; fresh weight is lower. We found no open fresh-weight values for G. esculenta in the papers we read.


• The gyromitrin content does not tell you what a meal will do, because people respond differently and the toxin is partly lost in cooking. [4] [7]


• Nutrient and "health" values do not apply: this is not an eating mushroom, and we give no composition table as a reason to eat it.


• The human toxic-amount estimate comes from older work cited second-hand; do not use it as a measure of safety.