Background & aim: Medicinal plants with natural active substances and with lower side effects could be used as effective drugs in the treatment of many diseases. In recent years, the effects of reducing blood sugar, lipids, pain relief back pain of Ducrosia anethifolia has have been reported. The purpose of this study was to investigate the effect of hydro-alcoholic extract of Ducrosia anethifolia on Testosterone hormone and the histological changes of testicle in male adult rats. Methods: The present experimental study was conducted on 56 male adult Wistar rats.  The animals were divided into five groups: the control group (without treatment), the sham group (received the solution via gavage for 21 days). The experimental group 1, 2, 3 received hydro-alcoholic extract of Ducrosia anethifolia with 140,280,560 mg/kg dose per the body weight were gavaged for 21 subsequent days. On 22nd day, the animals were euthanized and the rat testes placed in 10% formalin for evaluating the histological changes. The 5 micron- sections from testicle were provided and stained by the hematoxylin - eosin method. The blood serums were collected and the level of testosterone was measured. Data were analyzed using SPSS statistical software and Duncan test and ANOVA at the significant level (p <0.05). Results: Statistical analysis showed a significant decrease in the number of spermatocytes, spermatids, spermatozoa and testosterone levels in Groups 1, 2 and 3 compared with the control group and the sham group. Conclusion: According to the results of this study, the Ducrosia anethifolia extract reduces the number of germ cells, the level of testosterone and spermatogenesis in male Wistar rats.