An elemental diet of defined composition and simple chemical form was nutritionally tested in a variety of surgical patients. Complete absorption in the upper gastrointestinal tract and minimal fecal residue proved especially advantageous in patients undergoing abdomianl surgery, and the diet also showed usefulness in patients with feeding problems. The patients responded well clinically, although some of them showed taste fatigue. Minimal variations in blood coagulation and chemistry indicated that the diet was safe, at least as it was used in the patients studied.