Mouth ulcers in children are mainly caused by recurrent mouth ulcers, oral infections, and deficiencies of trace elements such as zinc or B vitamins, and can also be caused by trauma. Generally need to go to the hospital in time to clear the diagnosis, and then symptomatic treatment. Common causes 1, recurrent oral ulcers: mainly caused by genetics, environment, hard friction, local irritation and other factors, can be manifested as recurrent, separate round or oval superficial ulcers; 2, oral infection: mainly caused by oral infection with bacteria, viruses, etc. when the immunity of children is low. Common in herpes pharyngitis, hand, foot and mouth disease, etc., usually infectious; 3, lack of trace elements: usually zinc, vitamin B deficiency and caused by ulcers; 4, dental scratches: when there are caries, dental misalignment and other problems, the oral mucosa is easy to be scratched, etc., can also cause local traumatic ulcers, usually can be self-relieved. Treatment measures 1. Medication: Watermelon cream spray can be applied to the surface of the ulcer under the guidance of a doctor. If the symptoms are accompanied by fever, you can also combine oral antibiotic treatment. In case of recurrent mouth ulcers, pain relief treatment with lidocaine gel, anti-inflammatory treatment with gargles, oral tablets, cidium tablets, etc. are generally available; in case of micronutrient deficiency, vitamins and zinc supplements need to be taken promptly; 2. Daily care: pay attention to maintaining oral hygiene, such as using light salt water to rinse the mouth, and avoiding hard foods such as peanuts and walnuts to prevent further damage to the oral mucosa. Zinc vitamin B and other trace elements should be supplemented in time, eat more eggs, milk, kiwi and other foods, and get more sunlight and exercise appropriately to improve the immunity of children’s organism. Note for the current situation of oral ulcers, pay attention to avoid spicy and stimulating foods, such as spicy strips, fried chicken, etc., so as not to aggravate the symptoms. Although the oral mucosa problems brought about by dental problems are not serious, they also need to be treated promptly once dental abnormalities are detected.