One of every two Americans will be bitten by an animal or by another person at some point. Bites account for approximately 1% of all visits to emergency rooms; injuries inflicted by dogs are most common. The bacteria involved in infection of bite wounds include Pasteurella multocida, Staphylococcus aureus, Staphylococcus intermedius, alpha-hemolytic streptococci, Capnocytophaga canimorsus, and other members of the oral flora. Anaerobic bacteria are present in approximately one-third of bite wounds and are associated with the formation of abscesses and with relatively serious infections. P. multocida is found in infections of cat bites more than 50% of the time. The bacteriology of bite wounds inflicted by exotic animals reflects the animals' oral flora. Bites inflicted by humans are often more serious than those inflicted by animals. Infections of human bites are associated with alpha-hemolytic streptococci, S. aureus, Eikenella corrodens, Haemophilus species, and (in more than 50% of cases) anaerobic bacteria. The principles of management of bite wounds are discussed.