Background Legal highs – various products containing new psychoactive substances and hallucinogenic substances of plant origin reached Poland about 7 years ago. Chains of “smart shops”, i.e. shops selling psychoactive substances, have been operating in the European Union countries since 2005. They constitute a new and serious medical, social and legal problem. One of the objectives of a program called the EU Drugs Strategy 2013–2020 is to combat threats connected with new psychoactive substances, for example, by strengthening the current EU legislation. New psychoactive substances, which imitate the effects of drugs, appear and rapidly spread throughout the EU. At present, there is little information on the harmful impact of novel psychoactive substances on the human body. The data are mostly based on the analysis of these substances whose consumption caused severe damage to human health or even death [1]. The article features the case of a patient addicted to psychoactive substances (including legal highs) with toxic lung injury, which occurred after inhalation of these substances. The goal of this article was to raise the awareness among doctors with regard to a new potential source of toxic lung injury in Europe and to show that the “legal highs” present threat for health.