Background: The study was designed to investigate the effect of stem bark aqueous extract of Enantia chlorantha on the sperm parameters and the histo-architecture of the testis of adult Wistar rats treated with lead (IV) oxide. Methods: A total of 20 adult male rats weighing between 180 g-200 g were randomly selected into 4 groups (n=5). Group 1 was giving only phosphate buffered saline; Group 2 was treated with 150 mg/kg body weight of the extract; Group 3 was treated with 300 mg/kg body weight of the extract and destroying agent [lead (IV) oxide]; Group 4 was treated only with the destroying agent [lead (IV) oxide] orally once daily for 14days of experimental period respectively. Animals were sacrificed by cervical dislocation 24 hours after the last administration of 14 days of experiment. Testis was dissected out following abdominal incision, fixed in 10% formo saline for histological processing using H/E stain. Semen was obtained from caudal part of the epididymis for analysis. Results: The histological observation revealed that seminiferous epithelium was prominent showing its constituents; the spermatogonia as well as the spermatids and spermatocytes were quite obvious in the control rats and rats treated with the extract (Group 1,2 and 3) as compared with the negative control (Group 4) that received lead IV oxide only. The photomicrograph in group 4 revealed that the interstitial spaces were abnormally widened and the Leydig cells were not observable, hence destroyed. Sperm count, motility, viability and progressivity of the sperm of animals in Group 1,2 and 3 were excellent (P<0.05) while those in Group 4 were weak. Conclusions: The aqueous extract of stem bark of Enantia chlorantha maintained the cytological integrity of testes and viability of sperm motility and sperm count of the rats that were treated with the extract when compared with the control rats. This protective effect of Enantia chlorantha against the destroying agent used prophylactic might be due to its antioxidant property.