The abiding principles of antibiotic use in the surgical patient vary in the complicated pelvic surgery setting only in that some microbes likely to be encountered warrant minor variation in drug choice. Very early antibiotic administration, relatively large doses, and prompt association when the reason for therapy has been accomplished, are the keystones for treatment. Tissue levels of antimicrobial activity are the uniform therapeutic goal. We also prefer consistent selection of drugs known to be safe and believe that continuous infusion may enhance the overall protective effect. Preservation of normal host defenses enhances the action of all antibiotics.