Psilocybin is a psychoactive, low toxicity substance. It can be found in Psilocibe mushrooms. This substance is an agonist of serotonin receptors and affects the activity of the central nervous system. Moreover, psilocybin demonstrates regulatory activity of certain brain areas responsible for emotions, mood, memory and learning. The aim of this paper is to present the latest research studies on the use of psilocybin in treatment of depression, addictions and cluster headaches coming from different independent research centres. The scientific articles selected present only a fraction of all the published results, yet they show that psilocybin is a substance with untapped therapeutic potential. The study focused on specific afflictions, such as drug-resistant depression and depressive symptoms in terminal diseases, nicotine and alcohol addiction, and cluster headaches. Most recent results from various independent research centres were chosen. Psilocybin is a substance that requires much research on bigger groups of patients in order to be able to fully confirm its therapeutic effects, evaluate its safety of use, and determine its long-term effects. However, it is a substance worth paying more attention to, despite the controversy it may raise as a psychedelic drug.