The role of alcohol consumption in the etiology of colorectal cancer has been investigated in a case-control study conducted from 1985 to 1990 in the northern part of Italy, on 889 cases of colon cancer, 581 cases of rectal cancer, and 2,475 controls admitted to hospital for acute, non-neoplastic, nondigestive disorders. After allowance for age, education, study center, body mass index, and approximate total energy intake, no significant associations between alcohol intake and the risk of cancer of the colon or rectum were found (odds ratios [OR] for greater than or equal to 42 drinks/week cf none = 1.0 (95 percent confidence interval [CI] = 0.8-1.4) and 0.7 (CI = 0.5-1.0) for cancer of the colon and rectum, respectively). A significant increase in the risk of colon cancer with increasing alcohol consumption was, however, observed in females (OR for greater than or equal to 28 drinks/week cf none = 1.8 (CI = 1.1-3.0). While the results of the present case-control study do not suggest that alcohol plays a role in the etiology of colon or rectum cancer overall, they provide a hint for a weak association between alcohol consumption and colon cancer among females which, because of the similarities with breast cancer, should be evaluated in the context of the possible relationship between colon cancer, alcohol intake, and female hormones.