The prophylactic administration of antibiotic to the surgical patient is generally indicated whenever complicating infection of the incision or coelom to be violated is associated with a significant morbidity and/or mortality rate. For maximal benefit, antibiotic must be in the tissues at risk just prior to and throughout the entire period of bacterial contamination. When a parenteral route for delivery is uncertain, as in the case of shock or a burn wound, then topical application becomes a practical alternative. Only hospital surveillance, however, can dictate which patients and which surgical procedures warrant prophylactic antibiotic. Intelligently implemented, such a preventive programme can reduce significantly total expenditure for surgical health care.