There are no gender-specific factors for bad breath, so the causes of bad breath are roughly the same for men and women. Common halitosis is divided into physiological halitosis and pathological halitosis. Physiological bad breath is mainly caused by the intake of ginger, garlic, onions, leeks and other irritating food, or drinking coffee, strong tea, milk, alcohol and other beverages, as well as smoking, staying up late, poor oral hygiene and other factors, and can usually recover within a short period of time. Pathological halitosis can develop on the basis of physiological halitosis. Due to the morning, before meals, before going to bed without timely cleaning of the mouth, teeth, can lead to the accumulation of food residues embedded in the teeth, or oral secretions for a long time attached to the surface of the teeth, forming yellow deposits, or long-term eating sweets, fried food or other additives more food and not timely cleaning of teeth, etc., can cause bacterial breeding infection, can lead to the following common diseases and cause bad breath: 1. Caries: Bacteria accumulation on teeth can form plaque, while bacteria ingest sugar in saliva and decompose into acid, making further damage at the plaque and forming cavity, i.e. dental caries. When the food residue fills the cavity, if it is not cleaned in time, it will cause the food to deteriorate and produce bad smell; 2, gingivitis: due to the long-term accumulation of plaque on the teeth, and the formation of calculus, stimulating the gums can lead to gingivitis. In the role of inflammation, the gums can appear bleeding phenomenon, and can be accompanied by bad breath, local itching and other symptoms; 3, periodontitis: periodontitis is also related to plaque, calculus and other factors, while grinding, overbite caused by damage to the surface of the teeth, as well as food embedded in between the two teeth can also cause periodontitis. The main manifestation of periodontitis is bleeding, loose gums, can be accompanied by bad breath, periodontal abscesses and other symptoms; 4, bacterial infectious stomatitis: the human mouth can exist in a certain number of bacteria, when the patient is fever, infection and other physical decline, impaired immune function, bacterial activity, dysbiosis can lead to infection, mainly manifested as ulcers, erosion can occur in various parts of the mouth, the surface is often accompanied by gray-white pseudomembrane The main manifestations are ulcers, erosions, often with grayish pseudomembranes, and inflammatory halitosis. In addition to oral problems, diabetic ketoacidosis, pharyngitis, gastritis, lung infection, gastrointestinal metabolic disorders, vitamin deficiency, etc., may also cause oral odor, in which patients with diabetic ketoacidosis to exhale rotten apple breath as a characteristic performance. Therefore, if the phenomenon of bad breath occurs, after excluding physiological factors, patients can seek timely medical consultation according to their accompanying symptoms and actively treat the disease after identifying the cause.