DMBA was used to produce oral epithelial changes, from benign hyperplasia to epithelial dysplasia of different severity in golden hamsters. Thereafter, they were inoculated with candida albicans. The result shows that candidal infection can induce epithelial dysplasia in benign hyperplasia; and in epithelial dysplasia, candidal infection will promote malignant transformation. It implies that candidal infection of the oral leukoplasia should be detected and treated.