Dry mouth at night is usually considered to be caused by dry indoor air, can also be seen in kidney deficiency and other diseases, need to analyze the specific causes. Dry air, colds, fever, etc., can lead to dry mouth at night, resulting in evaporation of water from the body through the respiratory tract and skin, followed by symptoms of thirst. According to Chinese medicine theory, it is usually considered to be Yin deficiency and dryness, such as kidney deficiency. Yin deficiency and hyperactivity of yang, yin deficiency is heat, insufficient fluid and hyperactivity of yang, so thirst will occur. In addition, if there is a problem with the central nervous system, this can also lead to a phenomenon where the patient is thirsty, but the body is not actually dehydrated. Diseases of the immune system may also be accompanied by symptoms such as dry eyelids and conjunctiva. Patients can go to the endocrinology department of regular hospitals or Chinese medicine hospitals to clarify the cause of the disease. For dry mouth and tongue caused by Yin deficiency and heatiness, oral medication that nourishes Yin and clears heatiness can be taken under the guidance of a doctor. From the perspective of Western medicine, it is recommended to go to the hospital to improve the relevant examination, after a clear diagnosis for symptomatic treatment.