We experienced an autopsy case in which a 29-year-old woman committed suicide by parenteral application of a neuromuscular blocker combined with thiobarbital. These medicines were easily accessible to the victim who was an anesthesiologist in a hospital. Paralyzing the respiratory muscles the usual dose of neuromuscular blockers can cause death unless a breathing apparatus is used. Unusual medicines given in small doses are difficult to detect in the autopsy materials. In our case in the course of forensic investigation we successfully identified the traces of a neuromuscular blocker by mass spectrometry.