Dry mouth and bitter mouth may be due to too little water, diabetes, dry syndrome, uremia, reflux esophagitis and other reasons, you need to treat the cause of the disease with medication and other treatments. 1. Drinking too little water: too little water over a long period of time leads to a lack of water in the body, drink more water can be solved; living in a hot and dry environment, leading to water loss through sweat and dry mouth, need to pay attention to air circulation, to ensure that the indoor temperature is appropriate. 2. Diabetes: diabetic patients with increased osmolality of urine, resulting in osmotic diuresis, water loss and dry mouth. You can take metformin, glipizide, rosiglitazide and other hypoglycemic drug therapy or subcutaneous insulin treatment. 3. Dry syndrome: Salivary glands are attacked by autoimmune system errors, resulting in salivary synthesis and secretion disorders, so the mouth will be dry and bitter. It needs to be treated with hydroxychloroquine, methotrexate, azathioprine, cyclophosphamide, rituximab and other drugs. 4. Uremia: insufficient synthesis of antidiuretic hormone or decreased sensitivity of the kidneys to antidiuretic hormone, resulting in a large amount of urine formation and discharge, so dry mouth and bitter mouth. It can be treated with drugs such as desmopressin and ellagic acid pressin. 5. Reflux esophagitis: gastric acid and other gastric contents reflux into the oral cavity corrode oral mucosa, so dry mouth and bitter. Omeprazole, ranitidine, domperidone, aluminum magnesium carbonate and other drugs can be applied. Pay attention to the use of drugs under the guidance of physicians.