To clarifiy the activating effects of Buthus martensi Karsch(BMK) on tumor promotion in two-stage carcinogenesis in mice was investigated. In vivo system, BMK was seen to gave an inhibitory activity on TPA-induced mouse ear edema. In addition, the BMK was proved to have antitumor-promoting activity in two-stage mouse skin carcinogenesis induced by DMBA and two-stage mouse lung carcinogenesis induced by 4-NQO as a initiator plus TPA and glycerol as a promoter. Moreover, BMK significantly exhibited an cytolytic effect in HepG2 cells and showed significant antitumor activity against Sarcoma-180 bearing mice by oral administration. These results suggest that BMK could be effective in adjuvant chemotherapy for human cancer.