A system for total parenteral nutrition (TPN) with a 3-litre container (big bag) has been developed. The bag is filled by a pharmacist in the hospital pharmacy. One of four standard nutritional regimes can be chosen depending on the patients weight and estimated metabolic condition. The bags contain aminoacids, electrolytes, trace elements and energy in the form of glucose. Lipids with vitamins are given separately via a side port and not mixed into the bags. During one year 61 patients have been given a total of 846 bags. All patients, except for two, maintained or increased their body weight during TPN with the big bag system. However, almost all patients lost weight when TPN was exchanged for enteral or oral feeding. S-phosphate was initially low but normalized within one week in all patients. S-magnesium was low in 1/3 of the patients and remained low in 50% of those for the entire treatment period. S-calcium increased beyond the normal upper limit in 25% of the cases. S-albumin increased in all patients, except for those with metastasizing cancers. Fifteen positive cultures were obtained from big bags. Only in one patient, however, the same bacteria could be cultured from both the patient and the big bag. Some increase in infections related to central venous catheters was noticed. Better utilization due to increased amount of potassium, magnesium, phosphate and zinc compared to routine may be beneficial.