Three hundred twenty-seven bite injuries of the hand were reviewed for incidence of infectious complications. A policy to hospitalize all patients with human bite injuries was maintained, but noncompliance was high. Patients with uninfected or superficially infected bites (131) were hospitalized and treated with parenteral penicillin, cephalosporins, or clindamycin (mean duration, 45 hours). Among the 62 patients not lost to followup three minor septic complications occurred. Of similar patients not hospitalized (134), only two thirds received antibiotic therapy but no complications were observed. These data suggest that human bite hand infections can be averted and that established superficial infections can be successfully treated with outpatient antibiotic therapy. Of the 62 patients with moderately to severely infected human bites, 77% were injured by striking an opponent; 52% suffered injury over metacarpophalangeal joints. The mean delay in seeking medical attention was 2 1/2 days, compared to 1/2 day in the less severely infected group. Of the patients with more seriously infected bites, 94% received parenteral antibiotic therapy. Of 30 patients with known outcome in the latter group 27% suffered complications (stiffness; recurrent infection; other infectious complication), confirming the high morbidity of established deep hand infections secondary to human bites.