Among various alternative materials used in toxicological analysis the most important is hair, in which xenobiotics deposited create a possibility to observe the history of their administration in the period determined by the hair-length. In this paper the authors have tried to outline the course of the application of hair analysis in forensic toxicology for medicolegal purposes. The undertaken subject has been recorded in four cases of complex drug poisonings in which hair analysis was used in the toxicological evaluation. Drugs detected in the hair of the examined subjects inform about the history of pharmacological therapy in confrontation with those administered in order to commit suicide. The analysis confirms a model of dependence and proves drinking of alcohol and use of cocaine during the pharmacological therapy of dependence.