Substances that change the states of consciousness have been used in the therapeutics of traditional cultures for hundreds of years. In the Western cultural circle, scientific curiosity and hope for a breakthrough in the treatment of various mental disorders constituted the basis of the first wave of research on humans with the use of psychedelics. After synthesizing LSD, psychedelic substances aroused intense but short-term interest among mental health specialists at the beginning of the second half of the 20th century. In the preliminary studies, substances such as psilocybin or LSD, used as a supplement to psychotherapy, showed promising therapeutic effects, however, due to legal and political reasons, all research work was stopped in the 1970s. The last two decades have been a period of renaissance in the interest in using sychedelic substances in psychiatry. Despite the early stage of work, the clinical research conducted so far has indicated the potential benefits of using psychedelics in the treatment of anxiety, affective disorders, or addictions. Moreover, so far, no serious side effects of this form of therapy have been reported. However, due to a number of barriers of both medical and legal nature, the creation of the first psychiatric drug with psychedelic properties appears to be extremely complicated. Further, precisely constructed studies on large groups of patients are needed to determine whether psychedelics can find practical applications in psychiatric therapy (or even become a long-awaited breakthrough in the treatment of mental disorders).