Benign prostatic hyperplasia (BPH) is one of the common diseases in elderly men. Recently, the old-aged population has increased, with the interest in the clinical importance of BPH ever growing. This study is designed to investigate the effects of KH-305 on BPH induced rat. The herb formulation KH-305 is consisted of Rubus coreanus, Cornus officinalis and Cuscuta chinensis. An experimental prostatic hyperplasia was induced in male rats by the administration of testosterone propionate, 3 mg/kg SC, for 2 months. The rats were divided into 3 experimental groups: the control, BPH-induced, oral KH-305 ingestion group. After 2 months, the prostates were removed, and analyzed for their prostatic weight and histological examination. The prostate weights were measured in each group, and found to be 820${pm}$38mg, 3140${pm}$26mg, 1880${pm}$21mg in the control, BPH-induced, and oral KH-305 ingestion group, respectively. The BPH induced group showed statistically significant increases in their prostatic weights compared with control group(p<0.05) but oral KH-305 ingestion group showed more significant decreases than BPH-induced group statically(p<0.05). Histologically injected testosterone lead to prostatic hyperplasia in rats, but oral KH-305 ingestion decreased this change. These results suggest that KH-305 may be effective in treatment of BPH, and complementary medicine of BPH.