The effect of Sitosterol, a cholesterol lowering agent on the treatment of the benign prostatic hypertrophy(BPH) was investigated. Thirty patients of the BPH were studied for over six months with special references to the improvements of voiding symptoms, residual urine, uroflow rate prostatic size. Statistical analysis of the results showed that sitosterol induced significant improvements of obstructive urinary symptoms and uroflow rates in 24(80.0%) patients. There was no significant side effect. Therefore, sitosterol is considered to be effective for medical therapy of the BPH before undergoing any surgical intervention, particularly when surgery is contraindicated.