Psilocybe semilanceata belongs to the genus of Psilocybe; it is a hallucinogenic fungus, frequently found in regions with high rainfall, in the grass and moss. There are estimated to be as many as eight Psilocybe hallucinogenic species containing psychoactive alkaloids, such as psilocybin and psilocin, which may cause visual, auditory and other hallucinations, as well as profound changes in the perception of time and space. Since identification of P semilanceata in a form different than a fresh mushroom is almost impossible, the authors made an attempt at developing a method of fungi identification based on the PCR technique, which could be helpful in a fight against dangerous consumption of these hallucinogens by the youth. Detection of the specific DNA sequence for P semilanceata brought good results; the test may be commonly employed in forensic practice in the future.