Bad breath is not constipation, but it is related to H. pylori infection, indigestion, throat disease and oral disease. When the stomach is infected by H. pylori, it will affect the function of the stomach, which will lead to slow peristalsis, and the food in the stomach will stay for a long period of time, which will ferment and produce a lot of gas and bad breath. However, H. pylori has little effect on the intestines, so patients will not experience constipation. When the human body has indigestion, food reacts with digestive juices in the stomach, which will emit a sour smell and cause bad breath. Since the intestines cannot absorb the nutrients in the food, the peristalsis speed will be accelerated, so the patient will not experience constipation. In pharyngeal diseases, tonsillitis and maxillary sinusitis, when the condition worsens, can also lead to the presence of purulent substances and cause halitosis, but these diseases do not affect the function of the intestinal tract, so they will not be accompanied by intestinal symptoms. In oral diseases, periodontitis, dental caries, gingivitis, etc., can affect the taste of the mouth and cause bad breath, and will not be accompanied by intestinal symptoms.