Malegra 120 is a generic version of the popular drug Viagra, which is used to treat erectile dysfunction in men. It contains 120 mg of sildenafil citrate, a powerful ingredient that helps increase blood flow to the penis, resulting in a hard and sustained erection. Malegra 120 mg works by inhibiting the action of an enzyme called phosphodiesterase type 5, which is responsible for breaking down a chemical called cyclic guanosine monophosphate in the penis.