In real life, you often encounter the following situation, no matter how carefully you brush your teeth and pay attention to oral hygiene, you can still smell bad breath. Sometimes it is so severe that you can easily be disliked when you smell it yourself or when you talk to others. What exactly is the reason for the symptoms of bad breath? That is the presence of a bacterium, Helicobacter pylori (HP), in the gastric juice. This bacterium breaks down urotoxic substances in the mouth, producing the disgusting ammonia odor that is often smelled as bad breath. Although the odor is exhaled from the mouth, the cause of the disease is in the stomach. According to statistics, about half of the people in China are infected with H. pylori. Once infected with HP, besides causing bad breath symptoms, it also causes stomach discomfort, such as acid reflux, belching, upper abdominal fullness, pain, and even the possibility of stomach cancer. The scary thing is that this bacterium is contagious, and there is a certain clustering phenomenon in the family, sharing utensils, kissing, sneezing may be infected with this bacterium. The entire family is at risk of infection if there is a HP carrier in the family. For patients who are clearly infected with HP, a gastroscopy can be performed, which is mainly to observe the organic lesions in the stomach caused by HP infection. It is now becoming a patient consensus to eradicate HP when it is found. The treatment is a proton pump inhibitor combined with bismuth plus two antibiotics in the standard quadruple sterilization method, which can effectively eradicate the bacteria and relieve the trouble caused by bad breath.