For the doctors and other medical staff treating oral cancers, it is necessary to standardize basic concepts and rules on oral cancers to progress in the treatment, research and diagnosis. Oral cancers are integrated in head and neck cancers and are applied to the general rules on head and neck cancer, but it is considered that more detailed rules based on the characteristics of oral cancers are essential. The objectives of this 'General Rules for Clinical and Pathological Studies on Oral Cancer' are to contribute to the development of the diagnosis, treatment and research of oral cancers based on the correct and useful medical information of clinical, surgical, pathological and image findings accumulated from individual patients at various institutions.