We report an outbreak of scombroid poisoning at one kindergarten on September 25, 1997. There were 94 cases. The onset of symptoms of scombrotoxin after ingestion of fish is rapid (40 to 50 minutes after consumption). Clinical manifestation consisted of hyperemia, particularly on the face and neck (94.7%), nausea and vomiting (17.0%), abdominal pain (17.0%), pruritus (4.3%), headache and dizziness (4.3%) and diarrhea (3.2%). The duration of symptoms was 3 hours on average. Most patients responded to antihistamine very well. The poisoning was caused by the ingestion of spoiled scombroid fish. The tissues of scombroid fish had undergone a number of changes provoked by bacteria and the uncooked fish containing 2,104 ppm of histamine whereas cooked fish containing 1,980 ppm (198 mg/100 gm) of histamine was found in this accident.