Bad breath is not contagious, the cause of bad breath is divided into two types, one is caused by gastrointestinal disorders, the other is caused by oral diseases, no matter which cause of bad breath is not contagious to others. For gastrointestinal disorders caused by bad breath, you can regulate the stomach and intestines with a light diet, for oral disease causes bad breath, which requires targeted treatment. If there is too much calculus, ultrasonic cleaning is needed to completely remove the calculus in the mouth. If the bad breath is caused by dental caries, it is necessary to repair the cavity in time to avoid the fermentation of food inside the cavity to produce bad smell. In addition, if you are used to eating onions, garlic and other irritating food, there will also be bad breath, it is recommended to rinse your mouth in time after eating these foods to avoid food residues in the mouth residue, you can also drink a cup of tea can effectively remove bad breath.