False Morel Mushrooms (Gyromitra): Poisonous, How to Tell

• Cap: Brain-like, irregularly wrinkled cap, reddish-brown (sometimes chestnut, purplish-brown, or dark brown).
• Stem, ring and volva: Stem 3-9 cm long, 1-3.5 cm thick; not completely hollow in longitudinal section, with a cottony pith or irregular chambers.
• Where and when it grows: Officially classified as saprobic, though it may also form mycorrhizal relationships with trees; found mainly in coniferous forests, fruiting in spring.
• Range in North America: Widely distributed in northern and montane North America.

• true morels, Morchella species: True morel caps are honeycomb-like rather than brain-like and wrinkled.

Toxin: gyromitrin. Severity: can be fatal. Timing: Symptoms usually appear 5 to 12 hours after ingestion, though they can begin as early as 2 hours. A delayed start is the dangerous part: hours without symptoms do not mean the mushroom was harmless.

Call Poison Control at 1-800-222-1222 (U.S.) right away, or your local emergency number. Keep any leftover mushroom, a photo of it, and note when it was eaten. Do not wait for symptoms and do not try home remedies. This page does not give medical advice.

A clear photo of the whole mushroom, including the base dug out of the ground, the gills and a spore print, lets the app and a mycologist narrow down what it might be and flag features that match False morel. No photo, app or website can confirm that a wild mushroom is safe to eat. Use identification to know what to avoid, not what to cook.

Treat them as poisonous. The Michigan DNR says false morels should be considered poisonous and not eaten, and reports that some people who had eaten beefsteak morels for several years without problems later suffered acute poisoning, and a few died.

The reason some people still eat them is traditional preparation. Wikipedia notes that Finland allows sale only with mandatory warnings and preparation instructions, and that each round of parboiling cuts free gyromitrin to about a tenth; substantial toxin still stays in the mushroom, and the boiling fumes are themselves hazardous. Most European countries prohibit or discourage eating them. A Prince Edward Island foraging guide, PEI Untamed, also describes the exposure as cumulative. None of that makes a false morel a reasonable meal.

Wikipedia's Gyromitra esculenta article describes the course: symptoms usually start 6 to 12 hours after the meal, sometimes as early as 2 hours, with sudden nausea, vomiting and watery diarrhoea. Neurological signs such as dizziness, lethargy, vertigo, tremor and loss of coordination can follow, and a fever is common, which helps doctors separate it from other mushroom poisonings. The liver and kidneys can be damaged.

Hospitals use vitamin B6 (pyridoxine) for the neurological effects; it does not protect the liver. Wikipedia gives estimated fatal doses of gyromitrin of 10 to 30 mg/kg for children and 20 to 50 mg/kg for adults. If anyone has eaten a false morel, call Poison Control at 1-800-222-1222 (U.S.) now, before symptoms start.

A possible one, not a proven one. A 2021 study in the Journal of the Neurological Sciences (Lagrange and colleagues) investigated 14 cases of amyotrophic lateral sclerosis diagnosed between 1990 and 2018 among residents and second-home visitors of one hamlet in the French Alps. Genetic causes and environmental factors such as lead, radon and electromagnetic fields were ruled out. All patients had eaten wild mushrooms, notably false morels, and half reported acute illness after eating Gyromitra gigas.

The authors wrote that this supports the hypothesis that fungal genotoxins may cause motor neuron degeneration. It is an association in one small cluster, which is one more reason not to eat false morels.

• Outside. True morels have pits that look punched inward (Michigan DNR). False morels are ridged, wrinkled, lobed or brain-like and bulge outward.
• Inside. Cut lengthwise: a true morel is one hollow chamber. Gyromitra is chambered or has cottony pith; the Michigan DNR separates the beefsteak morel by its solid stem.
• Cap attachment. A true morel cap joins the stem. Verpa caps hang free, attached only at the top.
• Colour. The beefsteak morel develops a dark reddish colour with age (Michigan DNR).

The full step-by-step check, with season notes and prices for true morels, is on morel mushroom identification.

Gyromitra esculenta is a spring mushroom, mainly of conifer forests, and widely distributed in northern and mountain areas of North America. The Michigan DNR says it is very abundant in some springs there and that several Gyromitra species grow with or close to true morels. PEI Untamed associates false morels with spruce and pine, sometimes poplar, while true morels on Prince Edward Island favour apple, ash, elm, oak and poplar.

Sources give different windows, so plan for the widest one:

• WebMD (reviewed 22 August 2024): 6 to 24 hours after eating; sooner if the fumes were inhaled.
• Wikipedia's gyromitrin article: within 6 to 12 hours, as early as 2 hours in severe cases; most people recover in 2 to 6 days, and serious complications develop over 1 to 3 days.
• MedLink Neurology: gastrointestinal symptoms 5 to 10 hours or longer after eating, followed in some cases by liver and kidney injury and by neurological problems such as delirium and seizures.

The first symptoms are nausea, vomiting and diarrhoea, with muscle cramps, bloating and headache; severe cases can progress to liver failure, kidney failure, seizures, coma and death (WebMD). If anyone has eaten false morels, call Poison Control at 1-800-222-1222 (U.S.) right away, or your local emergency number. Keep a sample or photo.

Gyromitrin breaks down in the body to monomethylhydrazine (MMH). MedLink Neurology explains that MMH blocks the production of the active form of vitamin B6, which the brain needs to make GABA, its main calming signal; the result is overexcitation and seizures. Wikipedia estimates that about 35% of the gyromitrin eaten is converted to MMH.

That is why hospitals give high-dose vitamin B6 (pyridoxine). MedLink gives 25 mg/kg as an infusion over 30 minutes, repeated if needed; Wikipedia gives the same starting dose, up to a total of 15 to 30 g a day, and notes it treats the neurological effects, not liver damage. WebMD also lists activated charcoal. These are hospital treatments given by doctors, not something to attempt at home.

The numbers vary widely by country and period (Wikipedia's gyromitrin article unless noted):

• Poland, 1953 to 1962: 138 documented poisonings, 2 fatal.
• Sweden, 1994 to 2002: 706 calls to the poison centre, no deaths.
• United States, 2001 to 2011: 448 calls to poison centres.
• North American Mycological Association, a 30-year review: 27 cases, no deaths, 9 with liver injury and 3 with acute kidney injury.
• Minnesota, 1938: five deaths (MedLink Neurology).
• Case fatality: about 10% worldwide (Wikipedia); MedLink cites rates of 10 to 40% reported in other regions.

Low recent death counts in North America are not evidence that false morels are harmless; they reflect cases that reached poison centres and hospitals.

Yes, which is why 'morel mushroom sickness' is a search of its own.

• Raw or undercooked morels. In March and April 2023, 51 people fell ill after eating at one restaurant in Bozeman, Montana; 3 were hospitalised and 2 died. The morels were cultivated and imported fresh from China, eating them raw was more strongly linked to illness than eating them at least partly cooked, and symptoms began a median of 1 hour after the meal, mostly diarrhoea (90%), nausea (83%) and abdominal pain (68%). No specific toxin was identified. The CDC concluded that morels should be cooked before eating (CDC MMWR, 14 March 2024).
• A neurological syndrome. MedLink Neurology describes a French series of 129 cases after eating true morels: tremor in 53%, dizziness or a drunk-like feeling in 53%, visual disturbance in 22% and unsteadiness in 21%, starting a median of 12 hours after the meal (range 6 minutes to 48 hours).
• Stomach irritation. WebMD notes that even morels can irritate the stomach if not cooked properly.

None of this makes false morels less dangerous. It means illness after a morel meal still needs a call to Poison Control, and the identification should be checked.

Sources describe cooking false morels in ways that sound reassuring and then qualify it. WebMD says thorough cooking can technically remove the toxin but that even slight undercooking can leave enough to make you sick, and that cooking them in a poorly ventilated space is itself a poisoning hazard. Wikipedia describes gyromitrin as volatile and water-soluble and says repeated boiling mostly removes it; the existing section above notes that substantial toxin still stays in the mushroom. Poison Control states that people have been poisoned by breathing in cooking fumes. The practical conclusion is the one this page already gives: treat false morels as poisonous and do not eat them.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Nothing on this page says a wild mushroom is safe to eat. If you find an error, tell us and we will correct it.