We studied the effect of an anabolic steroid, oxandrolone, combined with a high-protein diet (2 g/kg/day) on the rate of weight gain and restoration of muscle function in the recovery phase after deep burns of 30 of 50% of total body surface (n = 7). The findings were compared with findings from an isocaloric (2 g/kg/day protein) diet alone (n = 6). The study was prospective and randomized. Data were also compared retrospectively with data from a group of burn patients treated in the same fashion using a high-calorie, high-protein diet with a protein content of 1.3 to 1.4 g/kg/day (n = 10). Muscle function was quantified using a physical therapy index defining rate of progress (0 = lowest, 10 = highest). Oxandrolone was given in the beginning of the recovery phase in a dosage of 10 mg orally twice a day. The recovery phase was defined as resolution of the hypermetabolic state using physiologic criteria. The study was performed in an acute burn rehabilitation facility where patients were transferred once entering the recovery phase. Patients in each group were not different with regard to age and burn size. We found that mean weight loss for all patients was 11 +/- 2% of preburn weight during the catabolic phase despite optimum nutrition and early wound closure. Data are presented as mean +/- SD. We found that the average weight gain during the first 3 weeks was 14.5 +/- 2.5 pounds and that the physical therapy index was 8.8 +/- 0.5 of recovery in the oxandrolone-protein group (n = 7); both of these values were significantly greater than the corresponding values in the other groups. In the high-protein alone group (n = 6), weight gain was 7.5 +/- 1.7 pounds and physical therapy index was 7.0 +/- 0.8. In the retrospective group (n = 10), weight gain was 4.4 +/- 0.8 pounds and function index was 4.1 +/- 0.5. The daily caloric intake was not different between groups. Protein content and oxandrolone were the variables. No side effects were noted with oxandrolone. We can conclude that an anabolic steroid combined with increased protein intake can significantly increase the rate of restoration of weight gain postburn.