Meromac Plus 1000mg/500mg Injection works by killing bacteria which can cause serious infections. It is used to treat many different types of bacterial infections such as infections of lungs (pneumonia) and urinary tract. It is given by a doctor or nurse into a vein and should not be self-administered. Meromac Plus 1000mg/500mg Injection usually makes you feel better very quickly but you should continue taking it as prescribed even when you feel better to make sure that all bacteria are killed and do not become resistant.