False morel
Gyromitra esculenta
- Known today as
- A brain-like, reddish-brown spring mushroom of conifer woods.
- Kind
- Fungus
- Constituents
- gyromitrin
- Poisoning
- Gyromitrin poisoning
- In other databases
- GBIF search · Wikidata search
Revised October 3, 2026: Checked against its sources, each read in full, in part, or in its abstract. Version 1, first published September 25, 2026.
Deadly. Deadly if not properly prepared, and not safe even then.
False morel: what was it used for?
Eaten after boiling twice in plenty of water in Finland, where it is still sold with a warning required by law; the Finnish Food Authority no longer recommends eating it.
False morel: what does modern science say?
Gyromitrin breaks down into monomethylhydrazine, a component of rocket fuel. The fumes of cooking can poison the cook; the toxin damages the liver, blood, and nerves, and is potentially carcinogenic.
False morel: is it poisonous?
Yes, and it can kill. Deadly if not properly prepared, and not safe even then. Its poisoning is gyromitrin poisoning: Six to twelve hours. Historical description, not medical advice; in a poisoning, call a poison centre.
Pharmacognosy & Toxicology
- Constituents
- gyromitrinhydrolysed to monomethylhydrazine
- Mechanism
- Monomethylhydrazine depletes pyridoxine and so the brain’s GABA, and injures the liver.
- Toxic dose
- Gyromitrin content varies between local populations; potentially fatal raw.
- Syndrome
- Gyromitrin poisoning
- Standing
- Sold with warnings in Finland; forbidden for sale in several countries.
- Michelot, D., and Toth, B. (1991). Journal of Applied Toxicology 11. Abstract read · the text read
The abstract of each source, beneath its citation. For Club members. About the Club or sign in.
Constituent names open the compound’s record at PubChem, and “ChEMBL” beside a name opens its record at ChEMBL, the European Bioinformatics Institute’s database of bioactive molecules. Where a mechanism line was checked against ChEMBL (ChEMBL 37, read 1 October 2026), the check is shown with the measured value and its source paper, or says plainly that nothing has been measured. Doses are as the references give them, for description only; this is not medical advice. Each source carries the result of its check against Crossref, PubMed, or the authority’s page: see Verification.
False morel: what lore surrounds it?
The “brain mushroom” divides cooks and toxicologists: a delicacy to some, a poison to others.
In Their Own Words
Atkinson reports that Gyromitra esculenta had long been reported edible and often eaten without harm, but that there were known cases of its acting as a poison.
“While this species has long been reported as an edible one, and has been employed in many instances as food with no evil results, there are known cases where it has acted as a poison.”
George Francis Atkinson, Studies of American Fungi. Mushrooms, Edible, Poisonous, etc., Chapter XVI (Morels, Cup-fungi, Helvellas), Gyromitra esculenta. Second edition; New York: Henry Holt and Company, 1903 (Project Gutenberg eBook #26492). The text, read in part
McIlvaine writes that fatal results had been charged to Gyromitra esculenta, formerly Helvella esculenta, but that its poisonous qualities were not proven.
“Helvella esculenta, now Gyromitra esculenta, to which are charged fatal results. The poisonous qualities of Gyromitra esculenta are not proven.”
Charles McIlvaine and Robert K. Macadam, Toadstools, Mushrooms, Fungi, Edible and Poisonous; One Thousand American Fungi, Introduction, on poisonous toadstools. Revised edition; Indianapolis: The Bowen-Merrill Company, copyright 1900, 1902 (Project Gutenberg eBook #51393). The text, read in part
Each passage is quoted from the text named, which the press fetched and read, and was checked word for word against a fresh copy of it; the link opens that copy. Passages are given as printed, without the editors’ footnote numbers, and with words broken across lines joined.
Sources
- Finnish Food Authority, guidance on false morel. Read in full · the text read
- Wikipedia contributors. “Gyromitra esculenta.” Wikipedia, The Free Encyclopedia. en.wikipedia.org/wiki/Gyromitra_esculenta (read 2 October 2026). Read in full · the text read
- Wikipedia contributors. “Monomethylhydrazine.” Wikipedia, The Free Encyclopedia. en.wikipedia.org/wiki/Monomethylhydrazine (read 2 October 2026). Read in full · the text read
- Finnish Food Authority (2025). Report: Nearly one-fifth of toxin remains in false morels despite boiling recommendation. ruokavirasto.fi (read 2 October 2026). Read in full · the text read
Verification
- Checked
- October 1, 2026, and October 3, 2026
- Passes
- Every sentence read against its sources, in the pass over the remaining 343 entries
- The Standing line checked against the authority it names (EMA, WHO, FDA, CITES, Commission E)
- Every dated or regulatory claim checked by category across the database
- Every source read, in full, in part, or in its abstract, and every sentence checked against what was read (October 3, 2026)
- Sources
- 5 cited: 4 read in full, 1 abstract read. 1 with the abstract on file.
- Corrections
- None were needed.
What was checked, how, and what was found is set out on the Verification page. A checked source is one whose record was found; it does not make the entry medical advice.
Cite This Entry
Version 1 · first published September 25, 2026 · last revised October 3, 2026
- Chicago
“False morel.” In Materia Medica, edited by B. C. P. Statema. Version 1. The Thinking Press, 2026–. Last modified October 3, 2026. https://thethinkingpress.org/materia-medica/false-morel.
- MLA
“False morel.” Materia Medica, edited by B. C. P. Statema, version 1, The Thinking Press, 3 Oct. 2026, thethinkingpress.org/materia-medica/false-morel. Accessed 8 Oct. 2026.
- APA
False morel. (2026, October 3). In B. C. P. Statema (Ed.), Materia medica (Version 1). The Thinking Press. Retrieved October 8, 2026, from https://thethinkingpress.org/materia-medica/false-morel
Club members keep entries on a shelf with private notes, print the plates as cards, and receive an entry by email each week. Create a free account before January 1, 2027 and all of it is yours for good. About the Club
See Also
Drawing on the same sources: Michelot
Nearby in the alphabet
Fennel (seed and water) · Fairy ring champignon (A small tan mushroom that grows in rings on lawns and pasture) · Fern seed (mistaken for seed) · Eyebright (Euphrasia officinalis and relatives) · Feverfew (Tanacetum parthenium) · The eye bead (white, light blue, and black, like an eye) · Fig (Ficus carica) · The exorcists’ manuals (above all those of the Franciscan Girolamo Menghi)
_(8489507598).jpg){kind=link}
Historical description, not medical advice.