There are two general causes of bad breath in infants, oral diseases and gastrointestinal diseases, the most common of which is caused by abnormalities in the function of the gastrointestinal tract, such as indigestion, food accumulation, constipation, etc. For oral diseases, poor oral hygiene, suffering from dental caries, gingivitis, periodontitis, oral mucositis, as well as tooth decay, periodontal disease and other oral diseases of children, their mouths are prone to breeding bacteria, especially anaerobic bacteria, the decomposition of which produces a sulfide, the smell, and 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, hard, hard to digest food; (3) give digestive foods, such as hawthorn, radish, yam, apple, etc.; (4) increase the intake of dietary fiber, to keep the stool open, to develop good bowel habits; (5) the symptomatic treatment (5) treat gastrointestinal diseases; (6) develop the habit of rinsing the mouth after meals, especially pay attention to eliminate the 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, the sleep time 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, long with 3 points of hunger and cold”, to avoid bad breath from the child’s spleen and stomach management.