Bad breath should be registered with stomatology and gastroenterology. The appearance of bad breath is related to oral diseases as well as digestive system diseases, so you need to choose the department according to different causes. For patients with bad breath caused by gingivitis, periodontitis, and dental caries, they need to go to the stomatology department for treatment of oral diseases. Insufficient gastric power in the digestive system, food stagnation in the stomach for a long time, food spoilage, fermentation will produce a bad smell and emit through the esophagus, which will also cause bad breath, this case should choose gastroenterology. Gastroenterology in the treatment of bad breath, mainly to restore the peristaltic function of the stomach, to promote the digestion of food in the stomach, the common drugs are Niuhuang Qing stomach pill, can clear the fire and reduce heat, eliminate bad breath. During the treatment period, you also need to avoid spicy and greasy food, otherwise it will affect the treatment effect.