Oral cavity with odor for the following reasons: 1, oral diseases, suffering from gingivitis, periodontitis, oral mucositis, cavities, periodontal disease and other diseases, their oral cavity is prone to breeding bacteria, emitting the smell of corruption to produce odor; 2, peptic ulcer caused by H. pylori, chronic gastritis, etc., H. pylori produces sulfur causing bad breath, the application of triple or quadruple therapy to eradicate H. pylori, oral odor can be significantly reduced; 3, functional indigestion, too much food accumulation in the human gastrointestinal tract, gastrointestinal peristalsis is too slow to cause oral odor; 4, weight loss or patients who can not eat, conducive to the growth of anaerobic bacteria to produce odor; 5, the elderly salivary gland function decline, also triggers the occurrence of anaerobic bacteria to produce odor; 6, smoking, drinking alcohol, often eat onions and acidic, spicy, stimulating food, easy to cause Oral odor.