Infection is an uncommon but unfortunate complication of prosthetic arterial bypass grafting. Because previously described methods of treatment of such infections which do not involve excision of the graft have not met with uniform success, we undertook a study of the efficacy of silver sulfadiazine cream in the treatment of Staphylococcus aureus infections of polytetrafluoroethylene carotid artery bypass grafts in dogs. At the time of bilateral grafts placement in 14 dogs, wounds were inoculated with at least 2 X 10(7) organisms. Three days later all wounds were opened. The wounds of seven dogs were treated with daily applications of silver sulfadiazine cream and the wounds of the other dogs were treated with daily applications of povidone iodine ointment. The dogs were sacrificed at 30 days or at the earliest evidence of arterial beeding from the wounds, whichever came first. Cultures of the wound were taken, and graft and artery histologic findings were studied at the time of sacrifice. Although survival of the dogs treated with silver sulfadiazine was marginally better than that of the dogs treated with povidone iodine, viable bacteria were present in microabscesses in many apparently healed wounds in the former group. We conclude that daily applications of silver sulfadiazine cream does not reliably eradicate staphylococcal infections involving polytetrafluoroethylene arterial bypass grafts.