Areca catechu (betel) nut is widely used as a chewing agent. The nut alkaloids have been implicated in the pathogenesis of oral precancerous lesions. Quantitative analysis of the chloroform extracts by gas-liquid chromatography of ten commercial nut samples from Bombay have shown a wide variations In their arecoline contents (0% - 1.4%; mean: 0.7%). Nut samples of Identical processing method also vary in their arecoline levels. These variations were suggested to be due to the difference In the raw materials and processing methods. Comparisons were made between the arecoline contents and the Incidence of oral precancerous lesions from the present studies and also from those of Kerala and Mysore. It was concluded that the difference in nut arecoline contents not only reflect their appeal, potency but also influence upon the incidence of these diseases.