Objective: To investigate the anti tumor effect and anti inflammatory activity of Boschniakia rossica (BR). Methods: The expression of tumor marker, GST P, p53 and p21 ras proteins in promotion stage of rat chemical hepatocarcinogenesis were examined by immunohistochemical technique ABC method. Anti tumor effect of BR was investigated by inhibitory test on Sarcoma 180 . Anti inflammatory activity of BR was tested by xylene induced mouse ear swelling method. Results: BR H 2O extract (the H 2O extract fractionated from BR Methanol extract with CH 2Cl 2 and H 2O) 500 mg/kg has inhibitory effect on the formation of diethylnitrosamine (DEN) induced glutathione S transferase placental form (GST P) positive foci in rat liver with the expression of mutant p53 and p21 ras proteins lower than those of non treated hepatic preneoplastic lesions. BR extract showed inhibitory effect on Sarcoma 180 and anti inflammatory effect in mice by xylene induced mouse ear swelling tests. Conclusion: BR H 2O extract exerted inhibitory effect on DEN induced preneoplastic hepatic foci in promotion stage of rat chemical hepatocarcinogenesis and might suppress the growth of solid Sarcoma 180 in mice. Both CH 2Cl 2 and H 2O extract from BR exerted anti inflammatory effect in mice. Objective: To investigate the anti tumor effect and anti inflammatory activity of Boschniakia rossica (BR). Methods: The expression of tumor marker, GST P, p53 and p21 ras proteins in promotion stage of rat chemical hepatocarcinogenesis were examined by immunohistochemical technique ABC method. Results: BR H 2O extract (the H 2O extract fractionated from BR M ethanol extract with CH 2Cl 2 and H 2 O) 500 mg/kg has inhibitory effect on the formation of diethylnitrosamine (DEN) induced glutathione S transferase placental form (GST P) positive foci in rat liver with the expression of mutant p53 and p21 ras proteins lower than those of non treated hepatic Preneoplastic lesions. BR extract showed inhibitory effect on Sarcoma 180 and anti inflammatory effect in mice by xylene induced mouse Ear swelling tests. Conclusion: BR H 2O extract exerted inhibitory effect on DEN induced preneoplastic hepatic foci in promotion stage of rat chemical hepatocarcinogenesis and might suppress the growth of solid Sarcoma 180 in mice. Both CH 2Cl 2 and H 2O extract from BR exerted anti Inflammatory effect in mice.