Although alcohol has not been demonstrated to cause cancer in laboratory animals, alcohol consumption in man is associated with an increased incidence of several types of cancer, usually in a dose-dependent fashion. All types of alcoholic beverage appear to be implicated, indicating the aetiological role of alcohol or its metabolites. The mechanisms by which alcohol induces cancer are unclear. Data concerning the relationship between alcohol and cancer come mainly from epidemiological studies (studies of groups and case-controls). Overall, for all types of cancer the relative risk, after adjustment for possible smoking, is 1.6 for the group where alcohol consumption is the highest (6 glasses or more per day). The most consistent relationships between drinking and risk of cancer are seen in this group, with the exception of the relationship between drinking and cancer of the liver.

The Agence Internationale de Recherche sur le Cancer (France) concluded that there is sufficient proof available of the carcinogenic potential of alcoholic beverages. The appearance of malignant tumours in the mouth, pharynx, larynx, oesophagus and breast may have a causal relationship with excessive consumption of alcoholic beverages.