OBJECTIVE: To review the risk factors for squamous cell carcinoma of the oral cavity, pharynx, and larynx. METHODS: Review of the literature using the Medline digital database (1980-2007). Previously published studies or studies not found in the database were included if relevant. Four types of studies were selected: (1) epidemiological, (2) toxicologic, (3) clinical, and (4) fundamental research. Publications concerning cancer of the nasopharynx were excluded. This work is based upon the ANAES guide for analysis of the literature and rating of guidelines, published in January 2000. RESULTS: The principal risk factors are tobacco and alcohol. Other risk factors, particularly infectious (viral) or environmental (nutritional and occupational), are also involved. From this analysis we conclude that: (1) most clinical and fundamental publications concern smoking and alcohol use; (2) studies of other risk factors are relatively old, especially those concerning nutritional and occupational factors; (3) most publications have a low level of scientific proof (grade C, levels 3 and 4). These 3 points explain the delay in the analysis of risk factors for upper aerodigestive tract (UADT) cancers. CONCLUSIONS: We must make up for this delay by prospective studies that include very large samples and use thorough and multivariate statistical analyses to estimate the impact of various toxic substances on the incidence of UADT cancer. This demands: (1) awareness on the part of all physicians who manage this type of cancer of the need to ask questions about exposure to risk factors besides than tobacco and alcohol; (2) collaboration between these physicians as well as with general practitioners, epidemiologists, nutritionists, and occupational physicians.