In this research, the genotoxic effect of Bupleuri Radix (BR), the dried roots of Bupleurum falcatum Linne has been traditionally used as anti-inflammatory agent, was evaluated using the mouse micronucleus test. BR aqueous extract (yield = 16.52%) was administered once a day for 2 continuous days by oral gavage to male ICR mice at doses of 2,000, 1,000 and 500 mg/kg. Cyclophosphamide (CPA) 70 mg/kg was used as a known genotoxic agent in a positive control. The appearance of a micronucleus (MN) in polychromatic erythrocyte (PCE) is used as an index for genotoxic potential, and PCE ratio is used as an index of cytotoxicity. Although significant (p<0.01) increase of the number of PCE with one or more nuclei (MNPCE) was detected in CPA treated groups, no significant increases of MNPCE numbers were observed in all three different dosages of BR extracts treated mice with over 0.30 of the individual polychromatic erythrocyte ratio in all mice used in this study. The results obtained indicated that BR extract shows no genotoxicity effects up to 2,000 mg/kg dosing levels the limit dosage in rodents.