A double-blind clinical trial with zinc sulfate, 0.2 g three times daily, and a placebo was performed in 30 patients with biopsy-proven alcoholic liver cirrhosis. The disease was in a stable phase, and none of the patients showed evidence of a decompensated liver function. Parameters of liver function, taste acuity, dark adaptation and of zinc and vitamin A metabolism were followed for six weeks. In the zinc-treated group of 16 patients, serum zinc rose from a normal mean value of 13.3 to 17.4 mumol/l, whereas the mean serum vitamin A level remained practically unaltered within the normal range, 1.89 at the entry and 1.83 mumol/l at the end of the study. Plasma prothrombin and serum alkaline phosphatase levels of the zinc group increased and serum bilirubin and serum carotene decreased significantly. The dark adaptation did not change, but the taste function was significantly improved during zinc treatment. The results indicate that zinc supplementation causes alleviation of certain abnormalities of cirrhotics, which deserves further attention.