There are many reasons for easy bad breath, in general, divided into physiological and pathological. The more common causes of physiological are the following: 1, and food-related, such as leeks, garlic, etc.; 2, and menstruation-related; 3, and psychological factors. Pathological bad breath in the more common causes are the following: 1, oral causes, such as gingivitis, dental calculus, tooth decay, etc.; 2, stomach causes, such as reflux esophagitis, bile reflux gastritis, Helicobacter pylori, etc.; 3, other causes, such as diabetes, uremia, etc.. Among them, the most common is still physiological causes, and among pathological causes, oral cavity is one of the most important diseases, rather than diseases of the stomach such as H. pylori.