psilocybin

American  

[sil-uh-sahy-bin, sahy-luh-] / ˌsɪl əˈsaɪ bɪn, ˌsaɪ lə- /

noun

Pharmacology.

1. a hallucinogenic crystalline solid, C 1 2 H 1 7 N 2 O 4 P, obtained from the mushroom Psilocybe mexicana.

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psilocybin British  

/ ˌsaɪlə-, ˌsɪləˈsaɪbɪn /

noun

1. a crystalline phosphate ester that is the active principle of the hallucinogenic fungus Psilocybe mexicana. Formula: C 12 H 17 N 2 O 4 P

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psilocybin Scientific  

/ sĭl′ə-sī′bĭn,sī′lə- /

1. A hallucinogenic compound obtained from certain mushrooms, especially of the genus Psilocybe. Chemical formula: C ₁₂ H ₁₇ N ₂ O ₄ P.

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Etymology

Origin of psilocybin

1955–60; < New Latin Psilocyb ( e ) genus of mushrooms (< Greek psīló ( s ) bare + kýbē head) + -in ²

Example Sentences

Dr. Steven Locke, a former Harvard Medical School psychiatry professor, wrote in an email that the question of whether psilocybin has any medical applications “remains controversial.”

From Los Angeles Times • Aug. 21, 2025

And what we found in that research too was that it wasn't obviously solely the psilocybin or the psychedelic components — it was that, compounded with untreated and unchecked grief for however many years.

From Salon • Aug. 28, 2024

But attempts to challenge the patents on Compass’ synthetic psilocybin have been unsuccessful, despite years of work by Turnbull’s patent watchdog group, Freedom to Operate.

From Seattle Times • Feb. 3, 2024

Rapid-acting antidepressants, including ketamine, scopolamine and psilocybin, have been found to have immediate and lasting positive effects on mood in patients with major depressive disorder but how these effects arise is unknown.

From Science Daily • Jan. 10, 2024

They established that psilocybin was first synthesized in mushrooms in the genus Psilocybe, with four to five possible horizontal gene transfers to other mushrooms from 40 up to 9 million years ago.

From Science Daily • Jan. 9, 2024