Objective To observe the protective effect of Bushen Jiedu Decoction on injury of reproductive system caused by nuclear radiation in male mice. Methods Sixty C57 BL/6 J male mice were randomly divided into blank control group

radiation model group and Bushen Jiedu Decoction group

with 20 mice in each group. Bushen Jiedu Decoction group was given Bushen Jiedu Decoction(13. 5 g/（kg·d） by gavage. The other groups were given 0. 2 ml of physiological saline by gavage. Each group was treated for 24 days. Except for blank control group

the other two groups received the whole body 5 Gy60 Coγ-ray radiation for one time on the eleventh day. The general physical signs of mice in each group were observed. On the first day and the fourteenth day after radiation

the weight of mice was measured and the testis index was calculated. The pathomorphological changes of testis and epididymis were observed on the fourteenth day with light microscope. Results In the radiation model group

the pathomorphology of testes and epididymides showed injuries in different degrees. The tissue structure in Bushen Jiedu Decoction group was basically normal. On the first day after radiation

compared with the blank control group

the weight and testis index of the mice in radiation model group and Bushen Jiedu Decoction group decreased significantly（P < 0. 05 or P < 0. 01）.The testis index in Bushen Jiedu Decoction group was higher than that in radiation model group（P < 0. 05）. On the fourteenth day after radiation

the weight and testis index in Bushen Jiedu Decoction group were both significantly higher than those in radiation model group（P < 0. 05）

and there was no significant difference between Bushen Jiedu Decoction group and blank control group（P > 0. 05）. Conclusion Bushen Jiedu Decoction group might reduce reproductive system damage caused by nuclear radiation and increase testis index.