Erythromycin is a type of antibiotic. Because there are many types of antibiotics, erythromycin belongs to the macrolide class of antimicrobials. Normal antimicrobials are divided into anti-bacterial, anti-fungal, including anti-parasitic, all collectively called antibiotics. The anti-bacterial ones are generally divided into many kinds, including penicillins, cephalosporins, macrolides, aminoglycosides, etc. They also include lincomycin and tetracycline. There are many types of antimicrobials, and each type belongs to the specific infection that corresponds to it before it can be used.