Within one decade the concept of clinical nutritional support has changed. It was once thought that total parenteral nutrition was an all-purpose panacea, and then that role was played by enteral nutrition. Recently, however, immunonutrition has emerged as a new methodology for nutritional support. Because of the pathologic complexity, numerous problems remain in nutritional support for surgical patients with severe infection. The best route of nutrition in the acute phase, actual efficacy of immune system-enhancing diets, and the prevention of bacterial translocation (BT) and Ventilator-associated pneumonia (VAP) should be resolved. This paper describes concerns in the clinical nutritional management of patients with severe infection and examines how the remaining questions are being resolved.