The current study is an endeavor for profound exploration about the effect of two brain stimulant medicinal herbs (Panax ginseng and Ginkgo biloba) alone or in combination on the im-provement of some physiological reproductive and thyroid activities in mature male rats. Forty mature male albino rats were classified into four equal groups (n=10). Group I control; received distilled water (1ml/day). Group II; administered with Panax ginseng only (200 mg/kg BW) Group III; administered with G. biloba only (150 mg/kg BW). Group IV administered with Panax ginseng + G. biloba (100 and 75 mg/kg BW) respectively. After 60 days of administration, serum level of reproductive (testosterone, LH and FSH) as well as thyroid (T3 and T4) hormones, some semen parameters, and histology of testicular tissue were evaluated. Serum level of testosterone hormone decreased significantly (P<0.001) in all groups while, there was no change in the level of LH and FSH. Moreover, T3 and T4 increased significantly (P<0.001) in all groups except in mixed group which showed non-significant increase in level of T3. Rats administered both herbs individually showed significant increase (P<0.001) in epididymal sperm count, abnormal sperm percent de-creased significantly (P<0.001) in all treated groups however, sperm motility significantly elevated (P<0.05) only in Ginseng received group. Histologically, testicular tissue of all rats disclosed en-hancement in testes by stimulating the activity of seminiferous tubules with mature spermatozoa. In conclusion Panax ginseng and G. biloba have improvement effect on semen parameters how-ever, serum testosterone hormone consumed in spermatogenesis process. Besides, both herbs have progressive power to synergize thyroid function ability by improvement level of thyroid hormones.