Sleeping up with a dry mouth may be caused by environmental factors, dietary factors, disease factors and other reasons. 1. Environmental factors: in the process of sleeping the body’s water will be with sweating, breathing and other ways to lose, if the bedroom air is dry, may lead to sleep up dry mouth. 2. Dietary factors: If you eat too much pickled products, barbecue, hot pot and other high-salt foods the night before, under osmotic pressure, it may lead to the loss of water between the tissues, resulting in a dry mouth. 3. Disease factors: for example, rhinitis, nasal polyps, etc., may be due to the symptoms of nasal congestion, resulting in decreased ventilation function of the nasal cavity, sleep affects the normal breathing of the nose, thus appearing to sleep with the mouth open, so that the water in the mouth continues to evaporate, so the mouth is dry in the sleep up. Dry mouth also occurs in dry syndrome due to abnormal secretion of salivary glands. It is recommended that patients place a humidifier indoors in the fall and winter seasons, do not consume too much high-salt food, and if they often sleep with a dry mouth, they should consult a doctor in time to avoid delaying their condition.