Spittle that saliva, normal people daily saliva total about 1000 ~ 1500ml, can maintain the basic function of the oral cavity. Physiological and pathological changes will trigger more saliva: a physiological changes: the human saliva secretion in every day is a certain pattern, the night sleep saliva secretion is very little, the morning saliva secretion is less, the afternoon saliva secretion increase, saliva will increase significantly after meals, young people in general saliva secretion is more than the elderly. In addition, factors such as food odor or conditioned reflex will also stimulate salivary secretion. Second, pathological changes: 1, respiratory diseases: respiratory diseases such as inflammation of the tonsils will cause sore throat, dysphagia, swallowing stimulation will increase saliva; 2, oral mucosal diseases: common, including oral ulcers, periapical periodontitis, pharyngitis, lingual inflammation, gingivitis, periodontitis, etc., will stimulate salivary secretion, so that increased saliva; 3, digestive diseases: common gastroesophageal reflux disease, patients because of a large amount of 3, digestive system diseases: common gastroesophageal reflux disease, patients because of a large amount of gastric juice, food and other reflux into the esophagus, and even pharynx, will stimulate the pharyngeal secretion increase, resulting in increased saliva; 4, other: central nervous system dysfunction, endocrine disorders, Alzheimer’s disease, epilepsy, heavy metal poisoning, and other conditions can also cause increased saliva. If physiological factors are excluded, early medical treatment is recommended. Daily attention should be paid to a light diet, avoid excessive consumption of some too acidic, too spicy food, stimulate saliva secretion.