The cause of keratitis needs to be clarified first, and then the corresponding ointment should be chosen according to the cause of bacteria, fungus, virus, allergy or malnutrition. 1. If the patient is a bacterial cause of keratitis, this case can be used for antibacterial drugs such as gentamycin, erythromycin and other ointments. 2. If the patient is a fungal cause of keratitis, such cases need to use miconazole, mycotoxin and other antifungal drugs made of ointment. 3. For viral keratitis, antiviral medications such as acyclovir can be used to treat the condition. 4. For allergy-induced xerostomia, ointments such as dexamethasone and chlorpheniramine, which are anti-allergic in nature, are needed. 5. For malnutrition-induced xerostomia, this condition requires the use of vitamins such as oral multivitamin tablets for symptomatic treatment. The specific use of drugs need to follow the doctor’s instructions.