The laughing gym (Gymnopilus junonius): is it psychedelic? What lab and genome studies found

“Laughing gym” is an everyday nickname for mushrooms filed under Gymnopilus junonius, a name that older papers wrote as G. spectabilis. The chemistry is mixed: one lab detected psilocybin in G. spectabilis in 1978 (Hatfield and Valdes, 1978), while Japanese chemists reported none in theirs (Kusano et al., 1986). A 2020 DNA study helps explain the split by showing that several species had been sharing one name (Thorn et al., 2020).

This page is about names, chemistry findings and records. It does not describe what the mushroom looks like or where it grows, and it is not an identification or edibility guide.

What is the laughing gym, and why is it called “laughing”?

The “laughing” comes from Japan. The Japanese name is ō-warai-take (written Ohwaraitake in one English abstract), which a 1992 symposium abstract says means “a loud laugh mushroom” (symposium abstract, 1992). A 1983 chemistry paper put it in its title as the “big-laughter mushroom” (Aoyagi et al., 1983). Two Korean papers, from the same research group, say it is widely known as the big laughter mushroom because eating it causes excessive laughter (Lee et al., 2020; Lee et al., 2024).

Those sentences report what the authors say the mushroom is known for. They are not clinical descriptions, and we did not find a case report we could open that documents the laughter. We also found no primary source for the English nickname “laughing gym” itself.

Is Gymnopilus junonius psychedelic? What did chemical analyses find?

The first report of psilocybin anywhere in the genus came from an accidental poisoning. In 1978 Hatfield and Valdes detected psilocybin in Gymnopilus validipes after that case, then screened 18 more Gymnopilus species with a method able to detect 0.0004% psilocybin in dried mushrooms. They detected it in G. aeruginosus, G. luteus, G. viridans and G. spectabilis, and noted that G. spectabilis had been reported to be hallucinogenic before (Hatfield and Valdes, 1978). The abstract does not say where the G. spectabilis material came from.

Japanese work points the other way. Kusano and colleagues isolated cerevisterol and a new acetylenic compound from G. spectabilis and wrote that psilocybin and related compounds “have not been detected in our collections” (Kusano et al., 1986). The 1992 symposium abstract repeats that no psilocybin or related compound had been found in Japanese o-warai-take, and that the authors went looking for a different active substance (symposium abstract, 1992).

Some later papers simply state, in their background sections, that the mushroom “contains” psilocybin, for example a 2008 study of Korean material (Lee et al., 2008). That paper did not itself measure psilocybin; it isolated other compounds. A background sentence like that repeats earlier literature and is weaker evidence than an analysis of the specimens in hand.

The fair summary: psilocybin has been reported from some collections under these names and not detected in others. Two things can produce that pattern. Collections differ in chemistry, and, as the next sections show, the collections may not have been the same species. Neither the 1978 nor the 1986 abstract can tell us which species, in today’s sense, its material was (Thorn et al., 2020).

What are gymnopilins, and what other compounds has the mushroom yielded?

Gymnopilins are long-chain compounds that two Japanese teams described in 1983 as the bitter principles of the mushroom (Aoyagi et al., 1983). Because psilocybin had not been found in Japanese material, the 1992 team tested fractions on newborn rat spinal cord and reported that the neuroexcitatory activity tracked the gymnopilins (symposium abstract, 1992).

Later lab studies built on that. Gymnopilins purified from wild G. junonius collected in Japan reduced acetylcholine responses in a nerve-derived cell line by acting on nicotinic acetylcholine receptors, and the authors suggest this “may be one of the causes” of G. junonius poisoning (Kayano et al., 2014). These are cell and animal-tissue experiments. They show what the compounds can do in a dish, not what happens in a person.

The genus has yielded other compound families too. Bis-noryangonin was reported from G. spectabilis in 1969 (Hatfield and Brady, 1969), and a 2008 Korean study isolated both bis-noryangonin and hispidin, two yellow styrylpyrone pigments, along with 4,6-decadiyne-1,3,8-triol (Lee et al., 2008). A 2020 study isolated trichothecene and tremulane sesquiterpenes and reported that two trichothecenes were strongly cytotoxic to cancer cell lines (Lee et al., 2020). None of these are psilocybin, and none has been shown to explain the laughing reputation.

Is it Gymnopilus junonius or Gymnopilus spectabilis?

Both names exist, and registries now treat them as the same species. Index Fungorum lists Agaricus junonius Fr. (1821) and Agaricus spectabilis Weinm. (1824), and gives Gymnopilus junonius (Fr.) P.D. Orton (1960) as the current name for both, with Gymnopilus spectabilis (Weinm.) A.H. Sm. (1949) as a synonym (Index Fungorum, spectabilis; Index Fungorum, Agaricus junonius). The older epithet, junonius, is the one in use.

That is why the 1969 to 2008 chemistry papers say spectabilis and the 2012 to 2020 papers mostly say junonius: the label changed, not necessarily the mushroom. GBIF’s backbone still holds the two names as separate entries, so its counts are split between them (GBIF, G. spectabilis in Ontario). Anyone counting records needs to add both, and then remember the next problem.

What did the 2020 DNA study find about the Gymnopilus junonius group?

A Canadian-led team compared DNA (the ITS and LSU regions) from mushrooms reported as G. spectabilis and G. junonius. They found that true G. junonius is widespread in Europe, South America and Australia, but that none of the limited sequences available from North America represent it (Thorn et al., 2020).

Instead they recognized five species of the group in North America: three already named (G. luteus, G. subspectabilis and G. ventricosus) and two new ones, G. voitkii and G. speciosissimus. They described a new species from Japan, Gymnopilus orientispectabilis, and gave the informal name /sororiluteus to a lineage known from sequences previously reported as G. spectabilis from China, Japan and the Russian Far East (Thorn et al., 2020). We read only the abstract, so we cannot say which specimens, Canadian or otherwise, the paper examined.

Japanese mycologists followed up. A 2022 conference abstract from Tottori University (not peer reviewed) reported that Japanese o-warai-take specimens fell into five lineages, including two of G. orientispectabilis, one matching /sororiluteus and one matching G. voitkii, and that the results supported the view that true G. junonius probably does not occur in Japan (Fujita et al., 2022). The renaming already shows up in the chemistry: the Korean group that called its mushroom G. junonius in 2020 called the big laughter mushroom G. orientispectabilis in 2024 (Lee et al., 2020; Lee et al., 2024).

For the psilocybin question this matters a great deal. If the Japanese collections that tested negative were G. orientispectabilis or /sororiluteus, and the American material that tested positive was something else again, the old results may be about different species. That is a reasonable reading of the two sets of papers, but no study we opened has re-sequenced the original chemistry vouchers, so it remains a hypothesis.

What does the 2024 genome study say about Gymnopilus and psilocybin genes?

The 2024 genome study of Psilocybe also traced the psilocybin gene cluster in other genera. Its gene searches recovered the four core psilocybin genes from published genomes of Panaeolus cyanescens and Gymnopilus dilepis, and from the authors’ own data for a specimen vouchered as Gymnopilus luteofolius and for Pluteus salicinus (Bradshaw et al., 2024). The Gymnopilus copies sit apart from those of Psilocybe, which the authors read as an ancient split, with more recent transfers between Psilocybe and genera such as Panaeolus.

On a separate DNA tree of the genera involved, the authors write that the most parsimonious reading is two independent gains in Gymnopilus: “the first acquisition in Gymnopilus is in G. aeruginosus ~22 mya with a second in G. junonius ~9 mya” (Bradshaw et al., 2024). The main text does not say which junonius-labelled sequence that estimate rests on; the details are in a supplement we did not open. The same paper used a G. junonius genome from the Joint Genome Institute only as an outgroup for its Psilocybe tree, and the main text does not report psilocybin genes in that genome.

So the genome evidence is suggestive but indirect for G. junonius itself. Genes are firmly reported from G. dilepis and a G. luteofolius specimen; a 2022 lab survey also measured psilocybin in a G. dilepis collection from Malaysia (Gotvaldová et al., 2022). For the wider story of how the genes moved between genera, see why magic mushrooms turn blue and the species and names directory.

What do Japanese poisoning reports say about o-warai-take?

We could not open a Japanese clinical case report, so we can only report what the research papers say about poisonings. A 2017 study from Japan lists G. junonius among five toxic mushrooms that have been involved in food-poisoning incidents in Japan, and designed DNA tests to detect it in fresh, cooked and simulated stomach-fluid samples (Nomura et al., 2017). The 1992 symposium abstract says accidental ingestion causes hallucinosis and abnormal behaviour (symposium abstract, 1992).

Those statements are summaries, not case data. They do not give numbers of patients, outcomes or how the mushroom was identified in each incident, and they predate the 2020 split, so “G. junonius” in a Japanese report most likely refers to the local species now under other names (Fujita et al., 2022). We do not describe effects beyond these sources.

Is Gymnopilus junonius recorded in Canada or Ontario?

Records exist under the name, but the 2020 DNA work means the name may not fit them. On 24 October 2026 the GBIF database held 38 Canadian records under G. junonius, 19 of them from Ontario (GBIF, G. junonius in Canada). Of the Ontario records, 16 are preserved specimens and 3 are observations, 11 come from the Royal Ontario Museum’s mycology collection, and the dated ones run from 1919 to 2023 (GBIF, G. junonius in Ontario).

Another 16 Ontario records sit under G. spectabilis, all preserved specimens, 14 of them in the Canadian National Mycological Herbarium, dated 1898 to 2001 (GBIF, G. spectabilis in Ontario). G. luteus, one of the North American species Thorn and colleagues recognized in the group, has 67 Ontario records, 64 of them observations, most from iNaturalist (GBIF, G. luteus in Ontario).

A record shows where someone wrote a name down, not which species the specimen is. We do not know whether any Ontario specimen filed as G. junonius or G. spectabilis has been re-sequenced since 2020, and the abstract we read does not say (Thorn et al., 2020). Our Ontario records guide explains how to read these counts, including the G. luteofolius records.

Is the laughing gym safe to eat?

Do not eat any wild mushroom that an expert has not identified. The Ontario Poison Centre says poisonous and non-poisonous mushrooms grow side by side and that only a mycologist can tell the difference; it also says not to wait until the person feels sick before calling (Ontario Poison Centre). The centre answers 24 hours a day, 7 days a week, at 1-844-POISON-X, or 1-800-268-9017 in Ontario (Canadian Association of Poison Centres). Call 911 in an emergency. Our guides to misidentification and who to call and poisonous mushrooms in Ontario explain why a name, a photo or a test result cannot clear a wild mushroom.

What we don’t know yet

• Which species, in the 2020 sense, the 1978 psilocybin-positive G. spectabilis material and the 1986 psilocybin-negative Japanese collections belonged to. No study we opened re-sequenced those vouchers.
• Whether G. orientispectabilis or /sororiluteus has been tested for psilocybin under its new name.
• Which junonius-labelled sequence sits behind the 2024 estimate of a psilocybin-gene gain “in G. junonius”, since the supplement was not opened.
• Whether any Ontario herbarium specimen labelled G. junonius or G. spectabilis has been redetermined, and to what.
• Where the English nickname “laughing gym” first appeared.

If a new paper settles any of these, we will update this page and log the change below. Until then, “laughing gym” is best treated as a nickname for a group of species, not a guarantee of any chemistry. For the bigger picture of what the term magic mushrooms covers, start with what magic mushrooms are.

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