External examination of the body in one case showed no significant findings, except for several needle scars in the left elbow bend. Internal examination revealed mild edema in the brain and lungs. Histological examination showed fatty liver and chronic active HCV hepatitis. The rectal temperature and the postmortem ambient temperature revealed hyperthermia. In the second case, external examination showed no significant injury except for a needle mark in the left thigh. Internally there was severe edema in the brain and the lungs. The tonsils and deep cervical lymph nodes were swollen bilaterally. There were no microscopic abnormalities except for mild tonsillitis. The police investigators estimated that MAP and MOR were injected shortly before midnight and early morning, respectively, when the death occurred. The rectal temperature and the ambient temperature before the autopsy suggested antemortem hyperthermia. A Triage screening test was positive both for amphetamines and opiates, but negative for cocaine in the urine samples in both cases. The two cases indicated death was due to synergism between MAP and MOR through hyperthermia. In both cases the MAP concentration or MOR concentration was not sufficient to cause death. Taken together, however, it is tempting to speculate that MOR enhances the hyperthermic effect of MAP to cause death. 1 table and 14 references