To determine the effects of nutritional support and recombinant human growth hormone (GH) on body composition and muscle function, we performed a randomized double-blind trial in 18 patients after elective gastrectomy or colectomy. Same amount of calories and amino acids were administered. Daily injection of GH or placebo was given during the first postoperative week. The GH dose was 0.2 IU/kg/d. The study of body composition demonstrated that control subjects lost lean body mass and fat 2.8 +/- 1.46kg and 0.49 +/- 1.3kg, respectively. In contrast, study group subjects lost the fat 0.95 +/- 0.46kg. Hand grip strength fell with time in the control group (P < 0.05). In contrast, grip strength of GH-treated subjects was significantly different from controls (P < 0.01). The study results demonstrated that nutritional support and growth hormone can maintain lean body mass and muscle function in postoperative patients.