Levomepromazine is among the oldest neuroleptics belonging to the phenothiazine group and has beneficial effects during the terminal stages of many illnesses. It offers combined antipsychotic, anxiolytic, and sedative activity, as well as analgesic properties. Results of previous toxicological findings in regards to levomepromazine suggest that the drug changes during the interval between death and autopsy. As such, the current case study offered an opportunity to collect postmortem blood during the interval between death and autopsy, and thus to test for any changes that may have occurred in the concentrations of xenobiotics found in the blood after death. The authors describe the materials and methods used to perform toxicology analysis. Postmortem venous brachial blood and femoral blood were sampled at 9 hours after death and then again at 31 hours after death. Results confirmed the differences in xenobiotic concentrations between time of death and autopsy. The authors conclude that the passive diffusion of xenobiotics in the body does indeed take place. Tables, references