It is possible to apply erythromycin ointment to blisters on the mouth, which is an infectious skin disease. In addition to blisters, pustules and pustules can be seen, and there is a certain itching and burning sensation, and redness can appear around the blisters. In addition to applying erythromycin ointment, oral roxithromycin capsules and azithromycin dry mix can be administered for antibacterial and anti-inflammatory treatment. If the blisters appear to be clustered in distribution, herpes simplex is considered, and topical erythromycin ointment should not be used at this time; acyclovir ointment can be chosen for antiviral treatment.