Psilocybe samuiensis is a psychedelic mushroom, which has psilocybin and psilocin as main active compounds. It was placed in the Section Mexicanae of genus Psilocybe by Gastón Guzmán due to its rhomboid-shaped spores. It has been found in Koh Samui, a small tropical island in Thailand, where some psychoactive species are consumed by both natives and tourists.