Erythromycin is a macrolide antibiotic that has an antimicrobial spectrum similar to or slightly wider than that of penicillin, and is often used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma and Legionellosis.

Erythromycin is a macrolide antibiotic used for the treatment of infections caused by certain types of bacteria. It is most commonly used to treat lung, throat, ear, skin, and sinus infections.