Mouth ulcers are one of the more common oral diseases, manifested as recurrent oral mucosal ulcers, which can occur singly or in any part of the mouth, with ulcers of varying sizes. When a child has a mouth ulcer, parents should do the following to relieve the child’s pain. One, keep the oral environment hygienic, give the child more water, water temperature should be moderate not too hot, so as not to damage the child’s oral mucosa. Second, a light diet, try to eat less spicy, pickled and other stimulating food, spicy easy to get on fire, pickled food is easy to lead to a reduction in oral fluids. Avoid rough, hard, too hot food, easy to cause mucosal damage caused by oral ulcers. Third, supplement vitamin B. The lack of vitamin B2 in the human body is likely to cause ulcers. Fish, meat, eggs and milk are good sources of vitamin B2, try to eat these types of food every day, as well as coarse grains are also rich in vitamin B2. With a rich diet every day, it is easy to meet the intake of B vitamins. Fourth, consume more fresh fruits or fruit juice to enhance the child’s immunity. If the child still does not get better after the above methods are used, the child should be taken to the doctor in time to avoid delaying the condition.