BACKGROUND : Ulmus macrocarpa Hance (UMH), of the family Ulmaceae, is a deciduous tree, widely distributed throughout Korea. UMH has been used as a traditional oriental medicine in Korea for the treatment of urological disorders, including bladder outlet obstruction (BOO), lower urinary tract syndrome (LUTS), diuresis, and hematuria. To date, its possible protective effects against benign prostatic hyperplasia (BPH) have not been analyzed. OBJECTIVE : This study investigated the effects of UMH on the development of BPH using a rat model of testosterone propionate (TP)-induced BPH. METHODS : BPH was induced by daily subcutaneous injections of testosterone propionate (TP) for four weeks. UMH was administrated daily by oral gavage at a dose of 150 mg/kg during the four weeks of TP injections. Animals were sacrificed, and their prostates were weighed and subjected to histopathological examination, TUNEL assay, and western blot analysis. RESULTS : Treatment of BPH-model rats with UMH significantly reduced prostate weight, serum testosterone concentration and dihydrotestosterone (DHT) concentration in prostate tissue. TP-induced prostatic hyperplasia and the expression of proliferating cell nuclear antigen (PCNA) were significantly attenuated in UMH-treated rats. In addition, UMH administration markedly induced the activation of caspases-3, - 8, and - 9 in prostate tissues of BPH rats, accompanied by upregulation of expression of Fas, Fas-associated protein with death domain (FADD), and Fas ligand (FasL) and a reduction in the ratio of B-cell lymphoma 2 (Bcl-2) to Bcl-2-associated X protein (Bax). CONCLUSIONS : UMH effectively inhibited the proliferation and promoted the apoptosis of prostate cells, suggesting it may be useful for the treatment of BPH.