Primary care physicians care for large numbers of patients presenting with "food poisoning" or gastroenteritis. When a patient who presents with acute gastrointestinal illness, especially in conjunction with neurologic or cutaneous symptoms, is evaluated, the history should focus on past seafood consumption (particularly raw or undercooked seafood). The infectious syndromes are generally self-limited and respond to supportive care; exceptions are those caused by Vibrio cholerae and Vibrio vulnificus, which may be fatal in severe cases. The toxic syndromes are uncommon and fall into two categories: the histaminelike syndrome of scombroid poisoning and the neurotoxic syndromes, including ciguatera, paralytic shellfish poisoning, and puffer fish poisoning. Recognition of these clinical entities may lead to more appropriate management and preventive measures.