Erythromycin is an antibiotic. It works on a slightly larger number of bacteria than penicillin, and does not provoke an allergic reaction in patients who are allergic to penicillin. It is often preferred for infections of the respiratory tract as it is effective against less common but more resistant infections. It is also routinely put in the eyes of newborns to prevent neonatal conjunctivitis.
It is often used on patients who have digestive problems related to poor or delayed emptying of the stomach. Like most other antibiotics, it affects the digestive tract and can cause vomiting and diarrhea. More rarely, it can cause arrhythmia and non-permanent deafness.
Unlike other antibiotics, erythromycin is destroyed by stomach acid. As such, when given orally, it must be coated or in a time-released formulation.