Gramocef-O 100 mg/5ml is an antibiotic belonging to the cephalosporin group which is used to treat a variety of bacterial infections. It is effective in infections of the respiratory tract (eg. pneumonia) urinary tract ear nasal sinus throat and some sexually transmitted diseases. Gramocef-O 100 mg should be given under the supervision of a doctor or health professional. Gramocef-O 100 mg is an antibiotic. It kills the bacteria by preventing them from forming the bacterial protective covering (cell wall) which is needed for them to survive.