There are many reasons for always wanting to drink water, commonly found in the following situations: 1, mental irritable thirst, patients tend to be more anxious and tense, drink a little bit of water to be able to slightly relieve this tension, anxiety, but it does not last long, so the patient has to keep on drinking water to keep their emotions stable for a long time, the antidiuretic hormone secretion is out of control, and they feel thirsty without drinking.2, hyperglycemia, hypercalcemia, when there will be osmotic diuresis, plasma osmolality is elevated, will stimulate the thirst center to feel thirsty.3, craniocerebral trauma, history of craniocerebral surgery or pituitary tumors caused by central urolithiasis, the daily urine volume can be up to 6L or more, the blood sodium is elevated, and stimulate the thirst center caused by thirst.4, rheumatism and immune system of the dry syndrome will cause a reduction in salivary secretion, the patient always feel dry mouth, need to drink a little water to increase the wetness of the oral mucosa.