For both genders, cancer of the mouth and pharynx ranks sixth overall in the world; it is also the third most common site among males in developing countries. In industrialized countries, men are affected two to three times as often as women, largely due to higher use of alcohol and tobacco. Ethnicity strongly influences prevalence due to social and cultural practices, as well as socioeconomic differences. In population terms, survival rates around the world show little improvement. In terms of etiology, the effects of tobacco use, heavy alcohol consumption, and poor diet together explain over 90 percent of cases of head and neck cancer. All forms of tobacco represent risk factors for oral cancer, but on present evidence, snuff habits as they exist in Scandinavia and probably in the United States carry lower risks of serious health hazards, including oral cancer. Alcohol synergizes with tobacco as a risk factor for all upper aerodigestive tract SCC: this is super-multiplicative for the mouth, additive for the larynx, and between additive and multiplicative for the esophagus. The increase in oral cancer in the Western world has been related to rising alcohol use.