The herpes mouth is likely to be caused by the following three causes: 1, viral infection: viral infections caused by herpes are common in the elderly and children rarely, because their resistance is poor, this time you can actively give nutritional support, local can apply acyclovir ointment for antiviral treatment, generally about 7-15 days will heal on their own. 2, allergies caused by herpes: the main manifestation is the blisters are too large, and the disease is more serious, the need for oral anti-allergy drugs for active anti-allergy treatment is also faster. Vitamin C, you can take oral vitamin complex for supplementation.