The different types of bad breath are caused by unclean mouth or bad habits, such as infrequent brushing, rinsing, too much dental calculus, dentures rarely cleaned and a lot of smoking can lead to bad breath. There are many causes of secondary halitosis, the common ones are: gastrointestinal diseases with fecal halitosis; oral diseases causing corrosive halitosis; respiratory diseases with bloody, putrid halitosis. In addition, diseases of the adjacent organs of the oral cavity can also lead to halitosis. A. What are the causes of halitosis? 1, caused by gastrointestinal diseases, such as peptic ulcer, chronic gastritis, functional dyspepsia, etc., may be accompanied by halitosis. Recently, we also found that the incidence of halitosis is significantly higher in those who are infected with Helicobacter pylori, which causes many gastric diseases, than in those who are not infected, and the symptoms of halitosis are significantly reduced after the eradication of Helicobacter pylori. The reason may be that H. pylori infection directly produces sulfide, causing bad breath. 2, oral diseases, suffering from dental caries, gingivitis, periodontitis, oral mucositis, as well as tooth decay, periodontal disease and other oral diseases, the oral cavity is prone to bacterial growth, especially anaerobic bacteria, the decomposition of which produces sulfide, emitting the smell of corruption, and bad breath. 3, smoking, drinking alcohol, coffee and often eat onions, garlic, leeks and other spicy food, or addicted to stinky tofu, rotten eggs and other smelly food people, also prone to halitosis. Long-term constipation, the harmful substances produced in the body can not be discharged in time, is absorbed into the blood and cause bad breath and bloating, loss of appetite, irritability and other symptoms of autointoxication. 4, dinner is too heavy, eat too much or into the meat, greasy food proportion is too large or spicy hot stimulating seasonings with too much, thick fragrance has more, light is not enough, dinner is too short from sleep time, sleep with too much food in the stomach and so on. 5, excessive psychological stress, regular mental tension leads to the body parasympathetic nerves in an excited state, reflexively appear digestive glands, especially salivary glands secretion is reduced, resulting in dry mouth, which is conducive to the growth of anaerobic bacteria, and halitosis. Second, what are the methods of treating bad breath? 1, before each meal, do more than ten deep breaths to help avoid bad breath. 2, usually pay attention to keep the mouth moist, drink water regularly. 3, people with persistent bad breath should insist on brushing their teeth after each meal. 4, actively treat diseases that cause bad breath, such as periodontitis, hepatitis, stomach disease, etc. 5, do not eat too much when eating, full meals tend to cause bad breath. 6, do not sleep too long, too much sleep is likely to cause bad breath. 7, bad breath caused by the consumption of irritating foods (such as garlic), can be eliminated by chewing tea, chewing gum or eating a few dates. 8, fasting time should not be too long, prolonged fasting can easily lead to bad breath. 9, develop the habit of rinsing your mouth after meals, especially pay attention to the removal of meat residue in the teeth, this kind of food containing high protein is most likely to cause bad breath. 10, before two meals, eat some fruit can help avoid or reduce bad breath. Bitter breath bad breath seems to be a small personal problem in life, if there is bad breath must be treated urgently, it not only seriously affects our social, and many diseases have a close relationship with bad breath, I hope these treatments can help.