Brolene eye drops and eye ointment contain the active ingredient propamidine, which is a type of medicine called an antibacterial. It is used to treat eye infections. Propamidine works by stopping bacteria from growing and multiplying, which controls the numbers of bacteria causing an infection. The remaining bacteria die or are killed by the body's immune system. This treats the infection. Putting the medicine directly into the eye allows the medicine to act directly on the bacteria that are causing the infection.