The cause of sticky mouth at night may be related to open-mouth breathing, Sjögren’s syndrome, periodontal disease and other factors. 1. Open-mouth breathing: If you have the habit of breathing with your mouth open when you sleep at night, it will cause a lot of evaporation of saliva in the mouth, and your mouth will become dry and sticky. 2. Sjögren’s syndrome: also known as dry syndrome, is an autoimmune disease. Due to the progressive destruction of exocrine glands, it causes dry mouth, dry eyes, hypertrophy of salivary glands and lacrimal glands, which can be manifested as sticky mouth and dry mouth at night while sleeping. 3. Periodontal disease: When periodontal disease exists, there will be a large amount of calculus and deep periodontal pockets will be formed. Due to the inflammatory reaction caused by the bacteria attached to the calculus, the gums become edematous and bleed or spill pus when probing. Symptoms such as sticky mouth at night and bad taste in the mouth may be present. Sticky mouth at night may have other causes, it is recommended to consult the doctor in time, improve the examination, clarify the cause and diagnosis, and standardize the treatment under the guidance of a professional physician.