In 1997 the Addiction Research Foundation of Ontario and Canadian Centre on Substance Abuse released updated guidelines for low-risk alcohol consumption. This paper presents the scientific rationale behind this statement. Important comprehensive overviews on the consequences of alcohol use were studied. Formal meta-analyses on morbidity and mortality were examined wherever possible. Individual elements from similar guidelines were investigated for their scientific foundation. Limited original analyses defined risk levels by average weekly consumption. The evidence reviewed demonstrated that placing limits on both daily intake and cumulative intake over the typical week is justifiable for the prevention of important causes of morbidity and mortality. Gender-specific limits on weekly consumption were also indicated. In these updated guidelines intended for primary prevention, days of abstinence are not necessarily recommended. Intoxication should be avoided and abstinence is sometimes advisable. Available evidence does not strongly favour one alcoholic beverage over another for cardiovascular health benefits.