Erythromycin ophthalmic ointment is a topical antibiotic applied directly to the eye to treat or prevent bacterial eye infections. It belongs to the macrolide class of antibiotics and works by killing the bacteria responsible for infection. It’s one of the most commonly prescribed eye antibiotics and is also the only FDA-approved medication used to protect newborns from eye infections acquired during birth.
What It Treats
Erythromycin ophthalmic ointment is used primarily for bacterial conjunctivitis, the type of pink eye caused by bacteria rather than viruses or allergies. Bacterial conjunctivitis typically involves thick yellow or green discharge, crusting on the eyelids (especially in the morning), and redness in one or both eyes. The ointment can also be prescribed for other superficial bacterial infections of the eye or eyelid.
It will not help with viral conjunctivitis, allergic reactions, or dry eye, even though those conditions can look similar. If your symptoms don’t improve after a few days of use, the cause may not be bacterial.
Newborn Eye Prophylaxis
One of the most widespread uses of erythromycin eye ointment has nothing to do with treating an active infection. It’s applied to newborns’ eyes shortly after birth to prevent a condition called ophthalmia neonatorum, a serious eye infection babies can develop from bacteria in the birth canal, including gonorrhea and chlamydia. The U.S. Preventive Services Task Force recommended in 2019 that all newborns receive erythromycin ointment within 24 hours of birth, and the CDC echoed that guidance in 2021.
That recommendation is evolving, though. A 2024 policy statement from the American Academy of Pediatrics supports “ongoing re-evaluation of the medical necessity of legislative mandates” for universal newborn eye prophylaxis. The American Academy of Ophthalmology now recommends continuing universal prophylaxis mainly where gonorrhea is prevalent, where routine prenatal screening can’t be ensured, or where state law requires it. Many states still mandate it by law, so most babies born in the U.S. still receive it.
How to Apply It
Applying ointment to your own eye feels awkward at first, but the technique is straightforward. Start by washing your hands. Tilt your head back and use one finger to gently pull your lower eyelid down and away from the eye, creating a small pocket. Squeeze a thin strip of ointment, roughly one-third of an inch (1 cm), into that pocket. Release the eyelid, then close your eyes gently and keep them shut for one to two minutes so the medication has time to spread across the surface of the eye.
Avoid touching the tip of the tube to your eye, eyelid, or fingers. Contact with any surface can introduce bacteria into the tube and contaminate the remaining ointment. If you’re treating both eyes, use the same technique on each one.
What to Expect During Use
The ointment is thick and greasy, which means it will temporarily blur your vision after each application. This is normal and usually clears within a few minutes. Because of the blurring, many people find it easiest to apply the ointment right before bed, especially if they only need it once or twice a day. If your prescription calls for more frequent applications during the day, plan to avoid driving or detailed visual tasks for several minutes after each dose.
Mild stinging or irritation when you first apply the ointment is common. Redness, swelling, itching that worsens, or signs of an allergic reaction (such as a rash around the eye or difficulty breathing) are not typical and warrant stopping the medication.
Finishing the Full Course
Bacterial eye infections often start to improve within two to three days, and it’s tempting to stop using the ointment once your eye feels better. Stopping early gives surviving bacteria a chance to multiply again, potentially causing a harder-to-treat recurrence. Use the ointment for the full number of days prescribed, even if symptoms resolve sooner.
Who Should Avoid It
The main contraindication is a known allergy to erythromycin or other macrolide antibiotics. If you’ve had an allergic reaction to a macrolide antibiotic taken by mouth in the past, let your provider know before using the ophthalmic form. Because the ointment is applied topically to the eye and very little is absorbed into the bloodstream, systemic drug interactions are not a significant concern with this medication.
Storage
Keep the tube at room temperature, between 59°F and 86°F (15°C to 30°C). Don’t store it in excessively hot areas like a car glovebox in summer, and don’t let it freeze. Keep the cap tightly closed when not in use. Once you’ve finished your prescribed course, discard any leftover ointment rather than saving it for future use, since the tube may have picked up bacteria during treatment.