Although alcohol is known to enhance hepatocarcinogenesis, the mechanism of this action remains to be explained. To test the hypothesis that ethanol depletes the liver of antitumor promoters such as retinoid, we measured the retinoid concentration in hepatocellular carcinoma tissues and noncancerous surrounding liver tissues in humans known to have a history of alcohol consumption. By high-performance liquid chromatography, the retinoid contents of 29 surgically resected hepatocellular carcinoma specimens and their noncancerous surrounding tissues were measured. Retinoid contents were decreased in both the cancerous and the surrounding noncancerous liver tissues of patients with a high intake of alcohol. The levels correlated inversely with the estimated cumulative lifetime ethanol consumption. The decrease in the retinoid content of hepatic parenchymal cells paralleled that in stellate cells. When compared with the surrounding liver tissues, the cancerous liver tissues were in the state of retinoid deficiency. In summary, alcohol abuse may help promote the hepatocarcinogenesis in man by depleting the liver of the antitumor promoter, retinoid. (HEPATOLOGY 1991;14:776–780).