Suddenly the mouth keeps secreting saliva may be oral hygiene unclean, nerve regulation abnormalities, oral diseases and other causes. 1. Oral hygiene unclean: the temperature and humidity in the mouth is more suitable for the breeding of bacteria, when the teeth and the food debris on the surface of the teeth to stay too much, so that the oral cavity is stimulated, resulting in a sudden mouth non-stop secretion of saliva. 2. Oral diseases: If the patient suffers from stomatitis, pharyngitis, inflammation of the tongue, mouth ulcers and other diseases, it will cause pain, and the salivary glands are stimulated, the secretion function will be exuberant, which will lead to non-stop secretion of saliva in the mouth. 3. Abnormal nerve regulation: when there is a conditioned reflex salivation, it will make the regulation of nerve reflexes impaired, resulting in the human body to appear suddenly mouth non-stop secretion of saliva. 4. Cerebrovascular disease: If cerebral infarction occurs, patients may have inflexible limb movement, crooked mouth, slurred speech, etc., and sudden salivation may also occur. It is recommended that patients go to the hospital in time for examination, according to the cause of targeted and effective treatment.