eriacta 100MG contains Sildenafil which belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors. It is used to treat adult men with erectile dysfunction, also known as impotence. It happens when a man cannot get, or keep a hard, erect penis suitable for sexual activity. Erectile dysfunction (ED) is the inability of men to attain and maintain an erect penis with sufficient rigidity to allow sexual intercourse.