Legal high are officially advertised as products for collectors and not as products to be taken by people, although they are commonly known for their psychoactive properties. Their producers advertise them as a legal alternative to the illegal drugs. So far there have been no scientific data concerning their toxicity and health hazards connected with using it. These products contain substances that have simulative, relaxing and hallucinogenic properties. Four cases of legal high poisoning treated in Department of Toxicology Raszeja Hospital in Poznań are presented in this study.