The problem of cancer is universal; the only variation occurs in the type, site or other clinicoepidemiological parameters. Peculiarly enough, oral cancers caused by chewing tobacco are common in India and some parts of the Indian sub-continent. Oral cancers caused by other carcinogens are not common in these areas. The present study shows a significant association (P less than 0.001) between the use of Indian chewing tobacco and oral cancer. Number of quids, mean quantity of tobacco and mean duration of keeping the quids in the mouth had direct dose and effect relationships in causation of oral cancer. A dose of 10 gms of chewing tobacco for about 26 years was observed to have produced cancerous lesions in the buccal cavity.