Objectives: to investigate the effect of SA-B on the 7,12dimethylbenz[a]anthracene (DMBA)-induced oral carcinogenesis in hamsters. Methods: 60 male Syrian golden hamsters were randomly divided into 4 groups, with two of 20 and two of 10. DMBA solution (0.5% in acetone) was applied topically to the left cheek pouch of male Syrian golden hamsters in group A and B, while animals in group C were painted with acetone, 3 times a week for 6 weeks. Animals in group D received neither DMBA nor acetone in the first 6 weeks. For the next 12 weeks, animals in group B and D received salvianolic acid B (10mg/kg /d) dissolved in saline by gavage, animals in group A and C received same volume of saline. At the end of the experiment, animals were sacrificed and tissue samples were collected for histopathological examination. Results: salvianolic acid B significantly decreased the squamous cell carcinoma (SCC) incidence from 47.1% (8/17) to5.6% (1/18)(p<0.005); But there was not significant difference in the number of other premalignant lesions between the salvianolic acid B treated group and the positive control group. The cheek pouch mucosa of the animals in Group C and Group D appeared normal. Conclusion: We conclude that salvianolic acid B may be a promising chemopreventive agent for oral cancer, but the detailed mechanism beneath this prominent effect needs further investigation.