Valif 20 mg contains the active ingredient Vardenafil, which is used to treat erectile dysfunction (ED) in men. Vardenafil belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. Vardenafil works by increasing blood flow to the penis during sexual stimulation, thereby helping men achieve and maintain an erection. It does this by inhibiting the enzyme phosphodiesterase type 5 (PDE5), which regulates blood flow in the penis.