Nowadays, complex poisonings with mixtures dominate among causes of fatal xenobiotic intoxications. Low consciousness of interactions between drugs, drugs and alcohol and drugs and narcotics has significant participation in this adverse occurrence. Especially dangerous drugs are neuroleptics, including phenothiazine-derivatives (PHD). The aim of this study was to analyze fatal complex poisonings with PHD in the practice of the Chair and Department of Forensic Medicine and Forensic Toxicology, Medical University of Silesia in Katowice in the years 1999-2008. The results of chemico-toxicological investigations of biological material, collected during autopsies from corpses of persons poisoned by mixtures, were analyzed, including a kind of phenothiazine, the presence of alcohol and narcotics and sex of casualties. In our material the complex poisonings with phenothiazines were the most often cause of fatal intoxications with these drugs. People liable to poisonings: the patients, drug addicts, alcoholics have to be educated about proper use of phenothiazines and possible interactions all the time. New, worrying phenomenon is the practice of prometazin' addition to home-made poppy straw extracts ('compote').