The purpose of the study was to evaluate the feasibility of nutritional therapy in a university hospital. Over a four-year period, 542 adult patients from 16 different departments were included in the study due to malnutrition and/or severe disease. Energy requirement including a surplus for weight gain was calculated by the factorial method and feeding was undertaken by means of food, liquid supplements, tube feeding or parenteral nutrition for an average period of 4.8 weeks. In patients with benign disease only, the average weight gain was as expected from energy balance but in patients with a benign stress-catabolic disease weight gain was only 40% of that expected. In malnourished patients with malignant disease, radiation- or chemotherapy could be carried out without further loss of body weight. During bone-marrow transplantation only a minor weight loss occurred. In conclusion, nutritional therapy is feasible in a clinical setting and the methods employed can identify groups of patients that require only nutritional support and other groups of patients that in addition require treatment of a stress-catabolic state.