The following reasons should be considered when waking up from thirst in the middle of the night: a. Diabetes mellitus, due to the increase of blood sugar, a large amount of water is excreted from the urine will lead to thirst and excessive drinking, accompanied by symptoms such as wasting and overeating. Dry syndrome, manifested as dry mouth, dry eyes, etc., due to autoimmune reactive diseases resulting in reduced secretion of salivary glands and other glands, belongs to a kind of connective tissue disease. Third, mental irritability, when patients due to excessive drinking, a large amount of water excreted with the urine, will appear the more you drink, the more thirsty, need to take the initiative to limit water, that is, limit the amount of water to drink without limiting the number of times to drink, so that after the total amount of water to drink decreases, the symptoms of thirst will improve on its own. Fourth, elderly patients can also experience dry mouth due to degenerative changes in the glands, which can lead to a decrease in saliva secretion.