An uncontrolled, retrospective study of 58 consecutive patients admitted to a hospital substance abuse unit assessed the effects of alcohol consumption on cholesterol levels. From the dietary histories completed by 54 of the patients, it was found that the alcoholics consumed a high-calorie diet containing a high percentage of foods with a high cholesterol content, but in small quantities. Most of their caloric intake was derived from the alcohol. Abusers of substances other than alcohol had a low-calorie intake of the same quality as alcoholics. It appears that low consumption of alcohol rather than something intrinsic in alcohol or other drugs is related to low levels of total cholesterol in persons consuming a high cholesterol-containing diet. The author also suggests that an unexplained relationship between low cholesterol levels and some gastrointestinal malignancies may be due to the effects of alcohol on the gastrointestinal tract.