In clinical practice, when taking a medical history, we often encounter patients with dry mouth, bitter breath and bad breath symptoms, and there are many reasons for these symptoms and they all appear at different times. Identify the cause and treat the symptoms. There are many causes of dry mouth, bitterness and bad breath, the main causes of which include: (1) oral diseases, such as tooth decay, gingivitis, periodontal abscesses and inflammation of the salivary glands, may cause symptoms of bad breath. When oral diseases cause bitter breath, pay attention to oral hygiene and control inflammation in order to treat bad breath. (2) Gastrointestinal diseases, such as chronic gastritis and gastric sinusitis, which can cause excessive stomach acid and symptoms of acid reflux and bad breath. In this case, you should take oral medication for stomach diseases to enhance gastric power, relieve acid reflux symptoms and treat bad breath. You should also pay attention to regular diet, do not overeat and pay attention to gastrointestinal protection. (3) From the perspective of Chinese medicine, bitter mouth is caused by excessive liver fire, which causes liver qi to invade bile qi, resulting in the formation of bitter mouth symptoms. Drink chrysanthemum tea and water to calm liver yang, drink more water, and pay attention to work and rest and emotional regulation. (4) When dry mouth symptoms are obvious, accompanied by dry eyes and other physical symptoms, you should be alert to dryness syndrome, which is an autoimmune related disease that affects salivary glands and leads to dry mouth, and you need to seek consultation from dentistry and immunology. In oral diseases and those with strong liver fire, bitter mouth and dry mouth appear almost all day long, and some may have severe bitter mouth symptoms in the morning. In gastrointestinal diseases, bitter mouth usually appears after eating and drinking. When the symptoms of bitter mouth appear, you should go to the hospital for examination and treatment according to the cause.