There are two general causes of bad breath in children: oral diseases and gastrointestinal diseases, the most common of which is caused by abnormalities in the function of the gastrointestinal tract, such as accumulation of food and constipation. For oral diseases, poor oral hygiene, children suffering from oral diseases such as dental caries, gingivitis, periodontitis, oral mucositis and tooth decay, periodontal disease, etc., their mouths are prone to breeding bacteria, especially anaerobic bacteria, whose decomposition produces a sulfide, which gives off a smell and produces bad breath. This condition is difficult to improve effectively through diet, and requires symptomatic treatment of oral problems, and bad breath can disappear. Bad breath caused by gastrointestinal diseases, such as peptic ulcer, chronic gastritis, functional dyspepsia, constipation, etc. can be improved through reasonable conditioning to improve the symptoms of bad breath. (1) adjust the diet, not too full at each meal, so that the child has some hunger, to promote gastrointestinal emptying, to give the stomach enough time to rest; (2) food is light and easy to digest, avoid fried, dry and hard, difficult to digest food; (3) to give digestive foods, such as hawthorn, radish, yam, apple, etc.; (4) increase the intake of dietary fiber, to keep the stool smooth, to develop good bowel (5) treat gastrointestinal diseases; (6) develop the habit of rinsing the mouth after meals, especially pay attention to the removal of meat residue in the teeth, such foods containing high protein are most likely to cause bad breath; (7) do not go to bed after a full meal, sleep should not be too long. Children’s spleen and stomach function is not perfect, too much and too fine food for children’s bodies is not necessarily good, but also the culprit of bad breath, as the saying goes, “to get a child safe, often suffer three points of hunger and cold”, to avoid bad breath from the management of the child’s spleen and stomach.