Tadalafil works by inhibiting the actions of specific enzymes (PDE5) in the body that restrict blood flow to the penis. This relaxes the blood vessels that supply the penis, increases blood flow to the penis, and keeps it erect throughout sexual intercourse. It also relaxes the smooth muscles that surround the bladder and prostate gland, improving urine flow and reducing the unpleasant symptoms of Benign Prostatic Hyperplasia.