Carcinogenicity studies of masheri, a pyrolysed product of tobacco.

The carcinogenicity of two commonly used brown and black varieties of masheri, a pyrolysed tobacco product, was studied by feeding the masheri through the diet at a 10% level to three different animal species of both sexes. In Sprague-Dawley rats, only brown masheri was used, while in Swiss mice and Syrian golden hamsters both varieties were used. In all the three species, forestomach papillomas were induced as a result of masheri treatment. In rats, 37% of animals showed forestomach papillomas while in mice and hamsters the incidence was 42-47% and 25-43%, respectively. No malignant changes were observed in any of the groups except 2/23 male hamsters showed forestomach carcinoma in the black masheri diet group.