Peripheral venous nutrition (PVN) has been proposed to avoid complications resulting from central venous catheterization in surgical patients. Using lipid emulsions 3 standard diets (with final osmolarity not higher than 900 mOsm/1, non-protein calories from 1675 to 2177, electrolytes 110 mEq, Cal/N ratio from 130/1 to 170/1) were worked out. They are suitable for total nutrition of non-hypercatabolic patients and for nutritional postoperative maintenance of patients undergoing major digestive tract surgery. The three diets were tested in 118 patients. Frequency and type of phlebitis and the nutritional status before and after treatment were evaluated in patients submitted to PVN and in 2 groups of 10 patients who received S-D5W infusions and Protein Sparing Nutrition (N = 12.8 g, total Cal. = 690, electrolytes = 110 mEq, osmolarity = 493 mOsm/l, pH = 7) in the postoperative period. Frequency of phlebitis was significantly lower in PVN patients than in control groups. 15 day treatment did not increase the frequency of phlebitis. In medium-term treated patients the mean daily nitrogen balance was always positive. Perioperative PVN achieved a statistically significant reduction of nitrogen losses with respect to PSN and S-DSW infusion.