Dry mouth and bitter mouth at night are caused by environmental factors, pathologic factors, dietary factors and other reasons. For those who suffer from dry mouth for a long period of time, it is recommended to have an examination in a regular hospital to clarify the cause of the disease and treat the cause under the guidance of a doctor. 1. Environmental factors: when people are in an environment that is too dry, low humidity, the symptoms of dry mouth and bitter mouth will occur, and the symptoms are more obvious when you wake up. It is recommended to replenish water in time. 2. Pathological factors: people with acute and chronic gastroenteritis, reflux esophagitis, diabetes and other diseases, dry mouth and bitter mouth, abdominal pain, diarrhea and other symptoms, this time should be timely medical treatment. 3. Dietary factors: When people eat too much salty, bitter food, dry mouth and bitter symptoms will occur. It is recommended to have a reasonable diet and moderate salt intake.