Erythromycin eye ointment is not recommended for long-term use, whether eye drops or eye ointment, more or less will contain a certain amount of preservatives, long-term use of eye drops containing preservatives may affect the normal metabolism of the eye, damage the eye cornea and conjunctiva and other structures, so long-term use of eye drops or eye ointment is not recommended, when the eye disease is cured, you can promptly stop the drug. Eye drops and eye ointments also have a certain shelf life. When opened for more than a month, the ingredients of eye drops and eye ointments may oxidize and deteriorate, and bacteria may also grow in them.