Health information to help you understand symptoms. It isn't a diagnosis.
Check symptoms

Erythromycin

Brand names: Ery-Tab, EryPed, Romycin (eye ointment)

Erythromycin is an antibiotic used for some infections in people allergic to penicillin. The eye ointment is put in newborns' eyes and treats eye infections.

Brand namesEry-Tab, EryPed, Romycin (eye ointment)
Type of medicineMacrolide antibiotic
Prescription?Prescription
ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.

Overview

It's also sometimes used to help the stomach empty.

What it's used for

  • Some respiratory and skin infections
  • Whooping cough
  • Eye infections and newborn eye protection (ointment)
  • Acne (gel)

How to take it

  • Take as directed; some forms need an empty stomach.
  • Finish the full course.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

  • Stomach cramps
  • Nausea
  • Diarrhea
Call 911Fainting or a fast, irregular heartbeat
Call your provider todayA baby under 6 weeks who vomits forcefully after feeds (rare stomach outlet problem)
Call your provider todaySevere watery or bloody diarrhea, even weeks after finishing (possible C. diff infection)
Call your provider todayYellow skin or eyes

Warnings

  • It can affect heart rhythm.

Other medicines, foods, and alcohol

  • It raises levels of many medicines, including simvastatin, lovastatin, colchicine, and warfarin's effect.
  • Other medicines that affect heart rhythm add to that risk.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Can be used in pregnancy when needed.

Missed doses, overdose, and storage

If you miss a dose

Take it as soon as you remember. If it's almost time for the next dose, skip the missed one. Don't double up, and still finish the full course.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.

Conditions it's used for

Sources

Last updated 2026-11-13.