During childhood, the prostate gland is very small, and by puberty when sex hormones are in full swing, the prostate gland increases to normal, about 20 g. With age, men can have varying degrees of prostate enlargement after the age of 45, and most clinical symptoms appear after the age of 50, but the etiology of prostate enlargement is still not completely clear. Old age and functioning testes are two important factors in the development of prostate enlargement. The development and normal physiological function of the prostaglandins requires adequate androgens to maintain. In the presence of androgens, the prostate gradually increases in size. Although increasing age leads to a decrease in the overall level of androgens, the prostate gland in the elderly has an increased ability to locally take up testosterone and convert it to dihydrotestosterone, so the prostate volume gradually increases and the development of prostatic hyperplasia shows a time-related progression. The functioning testes continue to secrete androgens that stimulate hypertrophy of the prostate gland. Histologically the prevalence of prostatic hyperplasia increases with age. The binding of dihydrotestosterone to androgen receptors on prostate cells also induces the secretion of various growth factors, which can contribute to nodule formation and cellular hyperplasia. It also interferes with the apoptosis of cells within the prostate tissue, again leading to an increase in prostate size. As we age, the imbalance of sex hormones in the body and the synergistic effect of estrogen and androgen may also be important causes of prostate enlargement.