Objective: To evaluate the effect of ethanol seed extract of Raphia hookeri (RH) on exogenous testosterone and estradiol induced benign prostatic hyperplasia in adult male rats. Methods: Male rats weighing 200 ± 10 g kg–1 had exogenous administration of testosterone and estradiol in staggered doses (three times weekly) for three weeks. The induced animals were divided into five groups. Groups 1 and 2 received extract at 50 and 100 mg kg–1 body weight (bw) by gavages for forty five days; group 3, fenasteride (0.1 mg kg–1); group 4, untreated for forty five days; group 5 (negative control), sacrificed after twenty one day of induction. Group 6 received extract (100 mg kg–1) and steroid hormones simultaneously; group 7 was normal control. Each group comprised of 6 rats. Results: Progressive weight gain occurred overtime in RH extract/fenasteride treated. Prostate specific antigen (PSA) level significantly p < 0.05 decreased in the treated groups compared to the negative control with the extract treated exhibiting more effective decrease with dose. Treatment with the extract/fenasteride led to significant decrease in testosterone to a level comparable to normal. The levels of catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH) in the RH treated were comparable to normal while in the negative control showed marked reduction. Similarly, the activity of thiobarbituric acid reactive substances (TBARS) in the extract group was within the normal range while showing significant increase in the untreated. The photomicrograph of prostate of the extract treated showed extensive shrinkage of glandular tissue. In contrast, glandular hyperplasia occurred in the negative control. The extract effectively reduced the size of the enlarged prostate gland exogenously induced. It also exhibited effective anti-oxidative activity. Conclusion: The extract attenuated hyperplasia and showed to be good prophylaxis against BPH.