Among 290 patients with primary oral cavity or oropharyngeal tumors, 57 used snuff exclusive of other known oral carcinogenic agents. They were primarily white women older than 60 years who had "dipped" snuff longer than 40 years. Carcinomas appeared preponderantly in the buccal (47.5%) and alveolar (31.5%) regions, coincident to the location of the "quid." Many that clinically looked like verrucous carcinomas were histologically well-differentiated squamous cell carcinomas and acted as other squamous cell carcinomas of the oral cavity do. Irradiation or resection were equally effective for the same grade of tumor. Fifty-eight percent of patients had recurrence or a contiguous second primary tumor; almost half (47.3%) had concurrent leukoplakia, and 13.9% had had leukoplakia excised previously, all related to the progressive panmucosal insult.