Objective:To investigate the impact of Humulus Lupulus L.hydroalcoholic extract on the body weights,reproductive organs,sperm quality and hormone levels in male rats.Methods:By simple random sampling method,seventy male Sprague-Dawley rats were randomly assigned to 7 groups including control group [distilled water,1 mL/(kg·d)],Tween 80 group [25％ Tween 80 solution,1 mL/(kg·d)],olive oil group [olive oil,1 mL/(kg·d)],diethyl stilbestrol (DES) group [DES,100 μ g/(kg·body weight)],H50,H150 and H450 [50,150 and 400 mg/(kg·d) of Humulus Lupulus L extract,respectively].The administration was performed via gavage once daily for 7 weeks.Body and reproductive organs weights including testes,seminal vesicles,epididymis and prostate were weighted and epididymal sperm quality were determined by digital balance.Blood samples were collected and serum free testosterone (T),luteinizing hormone (LH),follicle-stimulating hormone (FSH),and estrogen (E2) levels were measured by rat specific enzyme-linked immunosorbent assay.Results:The percentage increase in mean body weights of rats in the DES and H50,H150 and H450 groups decreased significantly compared to olive oil and Tween 80 groups (all P＜0.05).The weights of seminal vesicle,epididymis and testes in rats receiving H50 were significantly higher than the control group (P＜0.05 or P＜0.01).The sperm count in the rats receiving H50 was significantly lower than the control group (P＜0.05).The sperm motile characteristics of the rats receiving hydroalcoholic extract and DES were significantly lower than those of the control or rats receiving vehicles (all P＜0.05).In H50,H150,H450 and DES groups,T and LH levels were decreased,and E2 was significantly increased compared to the control (P＜0.05 or P＜0.01).The FSH level did not change in all groups (P＞0.05).Conclusion:Humulus Lupulus L.extract significantly increased the seminal vesicle and testes weights and reduced the sperm motility.