Erythromycin ophthalmic ointment is generally used to treat trachoma, conjunctivitis, blepharitis and infections outside the eye. The time of use should not exceed half a month. Erythromycin ophthalmic ointment belongs to macrolide antibiotics, the use of too long a period of time is easy to appear resistance, and anti-inflammatory effect is general, so patients are not recommended to long-term use. Erythromycin ophthalmic ointment occasionally see eye pain, vision changes, persistent redness or irritation and other allergic reactions. Erythromycin is contraindicated in people who are allergic to erythromycin. Avoid contact with other mucous membranes (e.g. mouth, nose, etc.) when using. If there is burning sensation, itching, redness or swelling at the site of application, the drug should be discontinued and the topical medication should be washed off, and the physician should be consulted if necessary. Patients are advised to use erythromycin ophthalmic ointment as prescribed by the doctor and not to prolong the time of use privately.