Infections in burned patients have generally been considered to arise from exogenous organisms. Consequently, the therapy of burned patients has emphasized the use of infection control policies and topical antimicrobial agents to reduce bacterial colonization. Even though enteric bacteria are frequently found in the burn wound little attention has been paid to the patient's own GI tract microflora as a potential source of organisms colonizing the burn wound. The current experiments were carried out to determine if the bacteria present in the GI tract of healthy animals would penetrate (translocate) through the GI mucosa and spread to visceral organs after a moderate or major thermal injury. The results of these experiments indicated that bacteria can translocate across the wall of the GI tract and survive in the mesenteric lymph nodes in healthy rats. Furthermore, when the GI tract microflora is altered, either due to bacterial overgrowth or under the influence of oral antibiotic therapy, not only will bacteria translocate to the mesenteric lymph nodes but bacteria will also spread to other visceral organs. The results of these experiments support the hypothesis that the GI tract can serve as a reservoir for nosocomial infections in the burned patient, since bacteria can translocate across the mucosal barrier of the GI tract after thermal injury and survive in visceral organs before colonization of the burn wound occurs.