Vega 100mg is a medication that contains the active ingredient Sildenafil Citrate. It is primarily used to treat erectile dysfunction (ED), a condition in which men have difficulty achieving or maintaining an erection sufficient for sexual activity. Sildenafil Citrate is a phosphodiesterase type 5 (PDE5) inhibitor, which means it works by relaxing the blood vessels in the penis, allowing increased blood flow and facilitating the achievement and maintenance of an erection when sexually aroused.