Dihydrotestosterone has an important role in the etiology and progression of BPH. Reduction of lower urinary tract symptoms and slowing down the progression of the disease is possible by the inhibition of 5-AR enzyme that converts testosterone to dihydrotestosterone. The main disadvantage of the treatment is effect of drug therapy occurs around six months. Efficiency of these agents are proved in many scientific studies and neither their long term safety nor their effect to reduce hemorrhage in patients undergoing surgery should not be forgotten.