The use of hypocaloric solutions of 3-5% amino acids, given through peripheral veins, is reviewed within the context of the protein-sparing concept. Because of technical problems associated with the use of central venous total parenteral nutrition, peripheral venous hypocaloric parenteral nutrition has been used in patients requiring short-term nutritional therapy who cannot receive adequate enteral nutrients. Partial parenteral nutrition is bases on the protein-sparing concept, which maintains that by simulating a mild fasting state in which body fat is used for energy, protein breakdown through gluconeogenesis is minimized if the patient receives adequate exogenous protein. Nitrogen balance is thus maintained at near-zero levels. Patients in whom protein-sparing therapy should be considered include well-nourished patients with normal adipose stores, skeletal muscle, and visceral protein, and who are expected to receive enteral nutrition in 7-10 days. Patients whose clinical status would be threatened by a slightly negative nitrogen balance or ketosis should not be placed on hypocaloric peripheral nutrition. Specific indications for peripheral infusion of amino acids are discussed. The use of hypocaloric solutions of amino acids through peripheral veins is a safer and less complicated technique than central venous total parenteral nutrition. The amino acids solution may be administered alone or with glucose, fat emulsion, or limited enteral feedings. Adverse effects are minimal; thrombophlebitis may occur with amino acid-glucose solutions but may be minimized by adding hydrocortisone and heparin to the infusion.