To evaluate the radioprotective effects of Bujeongsaengjintang studies were done experimentally. The results were obtained as follows: 1. WBC, Platelet and RBC were significantly increased in Bujeongsaengjintang treated group as compared with control group after exposure to radiation by Liniac. 2. By FACS analysis of splenic leukocyte after exposure to radiation by Liniac, T cell, T-helper cell and macrophase were significantly increased in Bujeongsaengjintang treated group. 3. In histological changes of ileum and jejunum of Balb/C mice after exposure to radiation by Liniac, exclusion and fusion of villi were decreased in Bujeongsaengjintang treated group as compared with control group. From above results, it is suggested that Bujeongsaengjintang is available to a clinic for the protection from damage by radiotherapy to cancer.