The present studies were designed to provide careful measures of effects of oxandrolone, an anabolic steroid, intravenous nutritional supplementation, and the combination of these two treatments on liver functions, metabolic balances, nitrogen metabolism, and nutritional status in patients with moderate to severe alcoholic hepatitis. Of 43 patients originally recruited, 39 (19 men, 20 women) with typical clinical and laboratory features of alcoholic hepatitis (11 Child's-Pugh class B; 28 class C) were admitted to a metabolic unit and completed a 35-day three-phase protocol. Phase I was a 10-day baseline period of observation, during which routine and special quantitative tests of liver function (galactose and antipyrine metabolism), a 7-day elemental balance study, and a 15N, 13C-leucine metabolism study were done. Phase II was a 21-day treatment period during which patients were randomly assigned to receive one of four regimens: 1) standard therapy, consisting of abstinence, a balanced, nutritionally adequate diet, and multivitamins; 2) oxandrolone (20 mg orally four times a day) plus standard therapy; 3) nutritional supplementation, consisting of 2 L daily of 3.5% crystalline amino acids (in 5% dextrose), given by peripheral vein; or 4) a combination of oxandrolone and nutritional supplementation, along with standard therapy. Metabolic balances were repeated during phase II. Phase III was 2 or 3 days posttreatment, during which special studies of liver functions and volumes and leucine metabolism were repeated. All patients who completed phase I of study and were randomly allocated to one of the four treatment groups completed the subsequent two phases. Overall, with time, patients showed highly significant improvements in most clinical and laboratory features. For most standard laboratory tests (e.g., serum albumin, transferrin, prothrombin time) improvements were more marked in patients treated with nutritional supplementation and/or oxandrolone than in those given standard therapy alone. Liver volumes fell in all treatment groups, with greater improvement in those treated with nutritional supplementation. Improvements in galactose and antipyrine metabolism rates were significant only in those treated with nutritional supplementation or oxandrolone. Effects of treatments on metabolic balances, nitrogen metabolism, and measures of nutrition are described in this issue in a companion paper. We conclude that the addition of nutritional supplementation and oxandrolone to standard therapy of moderately severe or severe alcoholic hepatitis is well tolerated, and leads to more rapid improvement in the laboratory parameters measured.