We have examined in vitro and in vivo radioprotective effect of a Chinese medicinal plants prescription, Lifukang. Micronucleus assay was employed to evaluate in vitro radioprotective effect of Lifukang. In the presence of Lifukang, the frequencies of miconuclei were greatly reduced from 7.2 to 2.9, 1.6 and 1.6% at the concentrations of Lifukang from 0 to 2, 10 and $50{mu}g/ml$, respectively. For in vivo assay, we monitored the incidences of apoptotic cells in mouse small intestine crypts and endogeneous spleen colonies. When Lifukang was administered to mice P.O. Or I.P. at doses of 1 mg/ml in drinking water for 7 days or 0.3 mg/mouse 24 hrs prior to irradiations, respectively, the average numbers of apoptotic cells were reduced to 3.1 or 2.3, respectively, as compared to 4.4 acquired from untreated control experiments. In addition, in spleen colony assay, Lifukang increased the number of hematopoietic spleen colonies. When samples were administered after irradiation, better results were obtained. The numbers of spleen colonies were increased from 14 colonies to 18.3 or 19.6 colonies when Lifukang was given through P.O. (1 mg/ml in drinking water for 11 days) or I.P. (0.3 mg/ mouse) after irradiation, respectively.