To investigate the importance of route of nutrient administration on septic complications after blunt and penetrating trauma, 98 patients with an abdominal trauma index of at least 15 were randomized to either enteral or parenteral feeding within 24 hours of injury. Septic morbidity was defined as pneumonia, intra-abdominal abscess, empyema, line sepsis, or fasciitis with wound dehiscence. Patients were fed formulas with almost identical amounts of fat, carbohydrate, and protein. Two patients died early in the study. The enteral group sustained significantly fewer pneumonias (11.8% versus total parenteral nutrition 31.%, p less than 0.02), intra-abdominal abscess (1.9% versus total parenteral nutrition 13.3%, p less than 0.04), and line sepsis (1.9% versus total parenteral nutrition 13.3%, p less than 0.04), and sustained significantly fewer infections per patient (p less than 0.03), as well as significantly fewer infections per infected patient (p less than 0.05). Although there were no differences in infection rates in patients with injury severity score less than 20 or abdominal trauma index less than or equal to 24, there were significantly fewer infections in patients with an injury severity score greater than 20 (p less than 0.002) and abdominal trauma index greater than 24 (p less than 0.005). Enteral feeding produced significantly fewer infections in the penetrating group (p less than 0.05) and barely missed the statistical significance in the blunt-injured patients (p = 0.08). In the subpopulation of patients requiring more than 20 units of blood, sustaining an abdominal trauma index greater than 40 or requiring reoperation within 72 hours, there were significantly fewer infections per patient (p = 0.03) and significantly fewer infections per infected patient (p less than 0.01). There is a significantly lower incidence of septic morbidity in patients fed enterally after blunt and penetrating trauma, with most of the significant changes occurring in the more severely injured patients. The authors recommend that the surgeon obtain enteral access at the time of initial celiotomy to assure an opportunity for enteral delivery of nutrients, particularly in the most severely injured patients.