As people’s awareness of oral health continues to increase, more and more people are coming into dental specialist institutions. The human mouth contains more than 700 kinds of about 105 bacteria, and the average saliva secreted by people under normal conditions is 1.5-1.7 liters per day. For how to maintain oral health, under normal circumstances, our mouth has the ability to self-cleaning, can remove food residues in the mouth and maintain the oral environment in a balanced state, to avoid the occurrence of oral diseases. This self-cleaning ability of the oral cavity is mainly through saliva secretion and tongue activity. During the daytime, people are awake, the oral cavity keeps secreting saliva to clean itself continuously. Saliva can play a role in stopping the formation of plaque, which can effectively prevent dental caries, periodontal disease and other oral diseases. The main functions of the tongue include swallowing, speech and chewing, etc. In the process of realizing these functions, the tongue gets movement, and the continuous movement of the tongue can remove the food residues in the mouth and keep the mouth clean. 1, clinical symptoms 1) oral dryness: early in the course of the disease, patients often feel saliva deficiency, dry mouth or sticky in the mouth. Loss of taste, painful tongue and corner of the mouth fragmentation, chewing and swallowing difficulties, etc. The dryness of mouth may cause waking up at night. Due to the decrease of saliva, tooth decay may occur easily. Oral examination often reveals the absence of salivary glands around the tongue ligament, and saliva secretion is not seen even when the salivary glands are massaged. (2) Dry keratitis and conjunctivitis: Patients often have foreign body sensation, burning sensation, itching and dryness in the eyes. In the early stage, there is often excessive tearing, and as the disease develops, the vision gradually blurs, eye redness, eye pain, and difficulty in opening the eyes in the morning, and later, when stimulated by foreign bodies or emotional excitement, no tears can be produced. Ophthalmologic examination shows congestion around the cornea, and sometimes enlarged tear glands are visible. 2.Treatment 1）Drink more water and rinse your mouth more often on a daily basis. 2) In general, you should eat more fresh vegetables and fruits. Because fresh vegetables and fruits not only contain a lot of vitamins and water, but also rich in crude fiber, must be fully chewed to swallow, and the process of chewing can effectively stimulate salivary gland secretion. Can often eat containing sour fruit more suitable, such as hawthorn, apricot, kiwi, strawberry, etc., to promote saliva secretion. 3）Dry and thin daily diet should be combined with food, and try to drink more soup, and pay attention not to be too salty at the same time. (4) If tooth decay is found, it should be repaired as early as possible, rinse your mouth after meals, brush your teeth with fluoride toothpaste in the morning and evening, and have an oral examination once every six months to a year, because many oral diseases can be found in the early stage and treatment measures can be taken as early as possible. Many diseases have no symptoms in the early stage, so it is difficult for individuals to detect them, and early detection is also beneficial to the control of the disease. Also focus on a balanced diet to avoid adverse effects on the oral environment.