Although continuous (24-h) total parenteral nutrition in hospital and discontinuous (cyclic) total parenteral nutrition at home are well-established, efficient methods of nutritional support, very little information is available on the early use of cyclic total parenteral nutrition in hospitalized, malnourished acute patients. In a prospective study, we used nocturnal cyclic total parenteral nutrition over 12-h infusion periods as a primary method of nutritional support in 27 consecutive acute patients hospitalized for severe malnutrition due to various gastrointestinal disorders. Mean duration of this method was 65 days (range, 21–170 days). The nonprotein energy source was provided by fat (40%) and hypertonic glucose (60%). After only 3 days of continuous intravenous feeding, the catheter was obturated and disconnected daily from 8 AM to 8 PM. The patients were totally starved during the day and were able to have various physical activities including washing, dressing up, and walking in and out of the wards. Cyclic total parenteral nutrition was associated with a significant improvement in nutritional status as assessed by weight gain, anthropometric measurements (p < 0.005), serum albumin (p < 0.01), nitrogen balance, and creatinine/height index (p < 0.001). Tolerance to treatment and acceptance of hospitalization were good in all patients but one. A low incidence of catheter infection (one case of septicemia due to a Staphylococcus epidermitis) and of metabolic complications (4 cases of consistent, reversible hypertriglyceridemia) was observed. It is suggested that nocturnal cyclic total parenteral nutrition is a safe, efficient, and psychologically well-tolerated method of nutritional support in hospitalized malnourished patients with severe gastrointestinal disorders. From an economic point of view, the daily cost of this method was 53% lower than that of patients treated in the intensive care unit for gastrointestinal diseases.