scombroid poisoning, toxic effects of eating scombroid fish (such as bonito or tuna) that have begun bacterial decomposition after being caught. Scombroid fish contain large amounts of free histidine in the muscle tissue, which gives rise to toxic levels of histamine under conditions of histidine decarboxylation by any of a dozen species of bacteria. Scombroid poisoning is not limited to consumption of fresh fish; the problem also may affect commercially canned tuna. Symptoms, which usually last no more than 24 hours, include nausea, vomiting, diarrhea, epigastric pain, and urticaria.
