Parenteral and enteral nutrition are safe and efficacious substitutes of normal oral intake even for prolonged periods of time and offer adequate treatment of protein-calorie malnutrition and effective palliation of cancer cachexia. Perioperative nutritional support reduces operative morbidity and mortality in malnourished patients. Furthermore, parenteral and enteral nutrition are an effective primary treatment for acute inflammatory bowel disease, short bowel syndrome and small bowel fistulae. Enteral nutrients specifically support structure and function of both the intestinal mucosa and the mucosa-associated lymphatic tissues: Recent clinical data emphasize the need to feed enterally whenever possible, especially in critically ill patients. Continuing efforts to include new substrates and to create more balanced and disease-adapted solutions of parenteral and enteral nutrition will improve the available systems. In addition, parenteral and enteral nutrition as a component of new complex treatment modalities including growth factors and cytokines will improve treatment and patient care in general surgery, oncology and traumatology.