Bite wounds, usually by dogs, cats, and human beings, affect one of two Americans during his or her lifetime and 1 to 2 million Americans annually. Despite the relative frequency of bite wounds, there are few prospective studies to define optimal care; consequently, diverse methods are used. In this article I review the incidence, bacteriology, clinical spectrum, complications, and treatment of animal and human bite wounds. The spectrum of pathogenic bacteria that cause bite infections is broader than is generally appreciated and includes both aerobic and anaerobic bacteria. Pasteurella multocida is found in only 20% to 25% of dog bite wounds. In choosing empiric antimicrobial therapy, clinicians must consider the diverse causative bacteria and their characteristic susceptibility patterns. Liberal irrigation and elevation of the injured part are also cornerstones of therapy. Early, aggressive medical and surgical management can minimize, if not prevent, complications.