Psilocybin is the active hallucinogenic compound mostly known to be present in magic mushrooms, which can be classified in more than 200 species of fungi. For the human body, once a phosphate group is removed from the molecule, which is called psilocybin, it subsequently becomes psilocin. After this, psilocin attaches to the 5-HT2A receptor. This receptor is part of serotonin, a neurotransmitter active in sleep, blood pressure control, mood, and depression, as well as in many other processes. It is thought that this binding reinforces interconnections of certain brain networks and modifies perceptual-cognitive functions, and may produce changes in psychological state(s).