Consecutive admissions (1020) for alcohol detoxification were evaluated. Twenty-two (2.2%) of the 990 patients without overt bleeding tested positive for the presence of fecal occult blood. Subsequent endoscopic evaluation of this population revealed a substantial prevalence of peptic ulcer disease (23.8%) and premalignant colonic neoplasia (31.6%). Upper GI mucosal inflammation was present in all patients. As in the general population, occult blood loss in the stool of alcoholics appears to be an important marker for colorectal neoplasia and to be of clinical significance in the prevention and early detection of colon cancer. Fecal occult blood should not be attributed to alcohol ingestion without the exclusion of coexistent pathology.