Puffer poisoning in Japan--a case report.

A fatal case of puffer poisoning in an 80-year-old man is reported. By using a bioassay with mice and extracts of crude poisons, the toxicities of the autopsy materials, fresh puffer ovaries, and the remaining cooked ovaries were determined and expressed in mouse units per gram (M.U.). Some medicolegal aspects of puffer poisoning are also discussed. Puffer poisoning is a primary cause of fatal food poisoning in Japan even though its frequency is not high.