There are many causes of dry mouth at night, including dietary factors, environmental factors, bad lifestyle habits, medication side effects, disease factors, etc.

1. Dietary factors: If you consume too much salty, spicy, and greasy food at dinner, the body will consume too much sodium, resulting in an increase in the osmotic pressure of extracellular fluid, which stimulates the hypothalamic osmoreceptors, resulting in a feeling of thirst and a dry mouth at night. For example, this situation is prone to occur after eating a large amount of salted fish, chili peppers and other foods.

2. Environmental factors: If the temperature of the sleeping environment is too high and the air is too dry, it will accelerate the evaporation of water in the human body. For example, in the hot summer, the lack of air conditioning or humidifiers in the room, or the use of heating in the winter and the lack of humidity in the room, can cause the body to lose a lot of water through the skin and breathing, which can lead to dry mouth.

3. Poor lifestyle habits: Some people have the habit of breathing with their mouth open, and the air enters the respiratory tract directly without being moistened by the nasal cavity during sleep, which will cause a large amount of water loss in the mouth, resulting in dry mouth. In addition, strenuous exercise before bedtime, heavy smoking, alcoholism, etc. can also accelerate the consumption of body water, causing dry mouth at night.

4. Medication side effects: Some medications, while working as a therapy, may have side effects of dry mouth. Antihistamines, for example, are often used to treat allergy symptoms, which inhibit the secretion of salivary glands; Certain diuretics in antihypertensive drugs, which lower blood pressure by increasing urine output, can cause the body to lose water, causing dry mouth; Antidepressants may also affect the nervous system's regulation of saliva production, causing dry mouth.

5. Disease factors: A variety of diseases can cause dry mouth at night. In diabetic patients, due to the increase in blood sugar, the kidneys will filter out more glucose and take away a lot of water at the same time, resulting in polyuria, and the lack of water in the body will cause dry mouth. Sjögren's syndrome is an autoimmune disease that mainly invades the lacrimal and salivary glands, resulting in decreased saliva production and dry mouth. Patients with hyperthyroidism have an increased basal metabolic rate, increased body heat production, increased sweating, excessive water loss, and dry mouth. In addition, diseases such as rhinitis and sinusitis cause nasal congestion and patients have to open their mouths to breathe, which can also cause dry mouth at night.

Dry mouth at night can be caused by a variety of factors, including diet, environment, lifestyle habits, medication side effects, and diseases, among others. If dry mouth occurs only occasionally, it may be relieved by adjusting your diet, improving your environment, and correcting your bad habits. However, if the symptoms of dry mouth persist or are accompanied by other uncomfortable symptoms, such as polydipsia, polyphagia, polyuria, dry eyes, joint pain, etc., you should go to a regular hospital in time for relevant examinations to determine the cause and treat it under the guidance of a doctor.

This article is only for health science popularization and does not constitute medication or medical guidelines, it is recommended to seek medical attention in time if you have health problems.