Psilocybin is a naturally occurring compound categorized as a psychoactive tryptamine that is found in some species of mushrooms. These mushrooms have been used for thousands of years by various cultures in order to achieve transcendent states of consciousness. In the 1960s, psilocybin was widely used in the experimental research of mental disorders and even in psychotherapy due to its therapeutic potential. However, psilocybin spread amongst the general public and became a popular recreational drug. Consequently, psilocybin was classed as a schedule I drug in 1970 and all human experiments were gradually discontinued. Since the 1990s, psychedelic research is being revived, and the properties of this substance have been rediscovered, becoming one of the most used psychedelics in human studies due to its safety.