Erectile Dysfunction (ED) is the inability of generating and maintaining erection hard enough to penetrate. It becomes more common in males above sixties. But male sexual dysfunction is not a natural part of aging. Erectile dysfunction is sometimes referred by the term impotence.

The penis contains two chambers called the corpora cavernosa, which run the length of the organ. The two chambers are filled with spongy tissues. The corpora cavernosa are surrounded by a membrane, called the tunica albuginea. The spongy tissue contains smooth muscles, fibrous tissues, spaces, veins, and arteries.

Erection begins with sensory or mental stimulation, or both. Impulses from the brain and local nerves cause the muscles of the corpora cavernosa to relax, allowing blood to flow in and fill the spaces. The blood creates pressure in the corpora cavernosa, making the penis expand. The tunica albuginea helps trap the blood in the corpora cavernosa, thereby sustaining erection. When muscles in the penis contract to stop the inflow of blood and open outflow channels, erection is reversed.