The two-stage carcinogenesis by 7,12-dimethylbenz[a]anthracene and 12-O-tetradecanoylphorbol-13-acetate (TPA) in mice was inhibited by kaempferol and flavonol glycosides, whereas naringenin, a flavanone, had no effect. The induction of epidermal ornithine decarboxylase activity by TPA was also