Bigfun 50 mg tablet belong to a group of medicine called PDE5 inhibitors. This medicine will only help get an erection if you are sexually stimulated. Bigfun 50 mg works by relaxing the blood vessels in peins.Bigfun 50 mg Tablet relaxes the blood vessels and helps in increasing the flow of blood to the penis.  This helps men to get or maintain an erection.This medicine will only help get an erection if you are sexually stimulated.