We report the case of a 30-year-old patient who developed scombrotoxic fish poisoning after eating cooked fresh tuna. Symptoms included a bright red rash, tightness of the chest, palpitations, anxiety, mild headache and dizziness, all of which resolved spontaneously within 2-3 h. Such poisoning results from the consumption of spoiled fish of the families Scomberesocidae or Scombridae - in particular tuna, mackerel, skipjack and bonito - which contain high levels of histidine. Incorrect storage of fish allows bacterial histidine decarboxylase to convert histidine to histamine. The ensuing symptoms are thought to result from the ingestion of histamine. Scombrotoxic fish poisoning is preventable by the correct handling and refrigeration of these fish.