Benign prostatic hyperplasia (BPH) is a common disease of the aged. And its etiopathogenesis is still uncertain after centuries' research. Ducts of prostate were often found obstructed and ectasy in pathological examinations. Recent studies suggest that pressure can facilitate the proliferation of prostatic cells. Therefore we hypothesize that ductal obstruction can induce augmentation of intraductal pressure and facilitate the proliferation of prostatic cells. Ductal obstruction might play a role in the etiopathogenesis of BPH. If our hypothesis can be further supported by future researches, it may change the present etiopathogenesis theory of BPH as well as the treatment strategies of it. (C) 2009 Elsevier Ltd. All rights reserved.