We report on two forensic cases suspected in connection with anaphylactic shock. Both the patients died just after an anesthetic administration during the operation. The blood histamine and tryptase concentrations of the victims were measured by GC-MS after ethylchloroformyl derivatization and fluoroimmunoassay, respectively. In the first case, the histamine and tryptase concentrations were 58 μg/ml and 25 ng/ml, respectively, were both significantly higher than the normal blood levels. In the second case, neither concentration exceeded the normal level.