Mouth ulcers and perioral dermatitis are two different diseases, in the clinic, the two attack parts, clinical manifestations are different. 1. Mouth ulcers is a kind of ulcerative injury occurred in the oral mucosa disease, common in the inner lip, tongue, buccal mucosa and other parts of the attack of severe pain, serious cases will affect the diet, speech, mainly through drug treatment, you can use anti-inflammatory drugs for anti-inflammatory pain, such as amoxicillin capsule, cefixime dispersible tablets, tinidazole tablets and so on, to promote the healing of the ulcers. 2. Perioral dermatitis is an inflammatory skin disease, clinically manifested in the upper lip, nasolabial folds, nose and other parts of the local erythema, papules, scales and other symptoms. It can be treated with moisturizing, anti-infective drugs such as metronidazole gel and erythromycin ointment. Severe cases can be treated with antibiotic drugs, such as doxycycline and minocycline. Mouth ulcers and perioral dermatitis clinical symptoms are different, when suspected of two diseases, need to go to the hospital in a timely manner, in the professional doctor’s judgment of scientific treatment, the above drugs need to be used under the guidance of the doctor.