The corns of the mouth are always bad, if it is infectious available erythromycin ointment topical, traumatic available saline wet compresses, contact available loratadine, etc.. 1. Infectious keratitis: often caused by bacterial and viral infections. Erythromycin ointment can be used for bacterial infections, and acyclovir cream can be used for viral infections. Allergic to the above drugs are prohibited. 2. Traumatic stomatitis: mostly caused by physical stimulation or licking the corners of the mouth, local treatment can be given, such as the use of saline rinse, wet compresses, while the surface can be coated with moisturizing lip balm. The bad habit of licking the corners of the mouth can be diagnosed. 3. Allergic keratitis: generally due to contact with allergens lead to the corners of the mouth red, swollen, congested, ulceration, can take anti-allergy drugs such as levocetirizine, loratadine, etc.. Allergy to the above drugs is prohibited. At the same time, improve the allergen test, avoid contact with allergens. The existence of keratitis, should be under the guidance of the doctor according to the cause of targeted treatment, in order to avoid recurrence, the use of drugs need to follow the doctor’s instructions.