Objective To determine the effects recombinant human growth hormone (GH) and hypocaloric nutrition on postoperative convalescence, we performed a placebo-controlled randomized double-blind trial in 18 patients after elective gastrectomy or colectomy. Methods The subjects received parenteral nutrition containing 20 calories/kg per day and 1 g protein/kg per day. Daily injections of drug or placebo were given during the first postoperative week. Result The nine control subjects lost 3.3 kg (5.9% of preoperative weight) and had a cumulative nitrogen loss of 32.6 ± 4.2 g nitrogen at eight days. The patients receiving GH lost significantly less weight (1.3 kg) and nitrogen loss was 7.3 ± 3.1 g at eight days (Plt;0.001). Kinetic studies demonstrated that anabolic effects of GH were associated with increased protein synthesis, and amino acid flus studies across the forearm revealed increased uptake of amino acid nitrogen in the GH-treated patients. Body composition analysis revealed that the patients receiving GH maintained their lean body mass despite the major surgical procedure. Conclusion We conclude that the postoperative catabolic response can be modified with GH and hypocaloric nutrition. The metabolic and physiologic effects should now be studied in a larger number of patients to determine if this approach can reduce morbidity, mortality, and length of hospital stay for surgical patients.