Thirst and dry mouth in the middle of the night may be caused by physiological reasons, may also be caused by pathological reasons, of which pathological reasons may be suffering from diabetes or uremia, dry syndrome and other diseases triggered. 1. Physiological reasons: if the food eaten before going to sleep at night is relatively salty, there may be the performance of thirst and dry mouth in the middle of the night; there is also a night sleep if snoring or open-mouth breathing, part of the water will be lost from the oral mucosa, which will also trigger the phenomenon. 2. Pathological causes: may be caused by diabetes, diabetic patients due to blood glucose has been in a high state, the thirst center will be stimulated, so that patients, whether during the day or at night there may be dry mouth and thirst symptoms; may also be caused by uremia, uremia triggered by thirst compared to diabetes will be more pronounced. In addition, it may also be caused by dry syndrome, the main symptom of the disease is dry mouth and thirst, serious patients have to drink water at the same time when eating or talking. If you exclude physiological causes of thirst and dry mouth in the middle of the night, you should consult a doctor in time, and cooperate with the doctor to do relevant examinations to clarify.