Benign Prostatic Hyperplasia (BPH), also known as benign prostate enlargement, is a non-cancerous enlargement of the prostate gland that commonly occurs as men age. The prostate is a small, walnut-sized gland located just below the bladder that produces fluid that is a part of semen. BPH affects the inner portion of the prostate, causing it to enlarge, which can press against the urethra (the tube that carries urine from the bladder out of the body) and leads to urinary problems.