A kind of medication used for the treatment of symptomatic benign prostatic hyperplasia (BPH), boosting the passage of kidney stones. It can also be used for the treatment of acute urinary retention. It is a kind of selective antagonist of alpha-1A and alpha-1B-adrenoceptros located in prostate, prostatic capsule, prostatic urethra, and bladder neck. The blockage of these receptors through Tamsulosin causes the relaxation of smooth muscles in the bladder neck and prostate.