Based on epidemiologic surveys conducted in 2007–2013, an increase in the consumption of psychoactive substances has been observed. This growth is noticeable in Europe and in Poland. With the ‘designer drugs’ launch on the market, which ingredients were not placed on the list of controlled substances in the Misuse of Drugs Act, a rise in the number and diversity of psychoactive agents and mixtures was noticed, used to achieve a different state of mind. Thus, the threat to the health and lives of people who use them has grown. In this paper, the authors describe the phenomenon of the use of plant psychoactive substances, paying attention to young people who experiment with new narcotics. This article also discusses the mode of action and side effects of plant materials proscribed under the Misuse of Drugs Act in Poland.