Patients with severe symptoms of bad breath may be due to the consumption of garlic, onions and other irritating foods or improper oral cleaning, poor hygiene, resulting in food residues in the mouth decay, resulting in increased bad breath. In addition, it may also be related to a variety of factors, such as oral diseases, ear, nose and throat diseases, respiratory system diseases, digestive system diseases, etc. 1, oral diseases: if patients suffer from oral diseases such as dental caries, periodontitis, pulpitis, etc., can lead to dental plaque, causing bacteria to multiply in the mouth, thus triggering the symptoms of bad breath; 2, ear, nose and throat diseases: if patients suffer from sinus infections, tonsils Ear, nose and throat diseases, such as stones, bacteria breeding or inflammation in the vicinity of the oral cavity can lead to infection, resulting in patients with bad breath; 3, respiratory system diseases: if patients have lung abscess, tuberculosis and other respiratory system diseases, local inflammatory reaction can occur, causing stimulation of the bronchial mucosa, accompanied by fever, coughing sputum, resulting in patients with putrid bad breath, bad odor and other symptoms; 4, digestive system diseases: if suffer from gastrointestinal inflammation, congenital esophageal stricture, intestinal obstruction and other digestive system diseases, the digestive function of the gastrointestinal tract is affected to a certain extent, which can cause excessive food and secretions to be retained in the gastrointestinal tract and produce a large number of corrosive bacteria, resulting in serious symptoms of halitosis. In addition, patients with gastroesophageal reflux can cause reflux of stomach acid and other components of the stomach into the esophagus, which can lead to increased bad breath.