If the baby has bad odor in the mouth, the following two conditions should be noted: First, the child may have indigestion, such as a history of improper feeding, which can cause indigestion, manifesting symptoms such as poor eating, nausea, vomiting, abdominal distension, abdominal pain, etc. You can give the child oral digestive drugs such as stomachic and antibiotic tablets for treatment, and pay attention to strengthening dietary care, eating light and easily digestible food recently. Secondly, if the baby does not brush the teeth diligently, after the fermentation of food residues left in the teeth, there can be a bad smell in the mouth. Therefore, when the child grows teeth, be sure to brush the child’s teeth every morning and evening to fully clean the mouth, and also rinse the child’s mouth after each meal to keep the mouth clean.