Vidalista 40 works by increasing blood flow to the penis, facilitating erections during sexual stimulation. The active ingredient, Tadalafil, belongs to a class of medications known as phosphodiesterase type 5 (PDE5) inhibitors. It works by inhibiting the action of PDE5, which regulates blood flow in the penis. By blocking PDE5, Vidalista 40 helps relax the smooth muscles of the blood vessels, allowing for improved circulation and firmer erections.