Quantitative methods were used to review epidemiologic data relating consumption of alcoholic beverages to risk of colorectal cancer. The data (27 studies) supported the presence of a weak association. For consumption of two alcoholic beverages daily, on average the relative risk of colorectal cancer was 1.10 (95% confidence interval 1.05-1.14). Other findings were: (1) the association did not vary according to gender or site within the large bowel; (2) results from follow-up studies (relative risk 1.32, 95% confidence interval 1.16-1.51) suggested a stronger relationship than those from case-control studies (relative risk 1.07, 95% confidence interval 1.02-1.12); and (3) the evidence supporting beverage specificity was not conclusive, although the results were consistent with a stronger association with consumption of beer (relative risk 1.26, 95% confidence interval 1.13-1.41) than with consumption of wine (relative risk 1.11, 95% confidence interval 0.91-1.36) or liquor (relative risk 1.13, 95% confidence interval 0.99-1.29). Because the magnitude of the association between alcohol consumption and risk of colorectal cancer was small, the findings regarding a causal role of alcohol were inconclusive.