Usually the purpose of oral care is mainly to improve the oral environment, prevent diseases, and observe the oral condition. In clinical practice, it is commonly used for patients in coma, mobility problems and special oral conditions, while in life, normal people can also maintain good oral hygiene and prevent common oral diseases through oral care. Since the oral cavity can contain a variety of dirt and pathogenic microorganisms that cause disease when the body’s immunity decreases, oral care has some importance.1. Improve the oral environment: Oral care can help keep the oral cavity clean and moist, and remove tartar and food debris, improve oral odor, and maintain normal oral function. In addition, it can improve the patient’s comfort and help improve appetite; 2, disease prevention: mainly to prevent oral infection, which can remove pathogenic agents in the mouth and prevent the occurrence of dental caries, periapical infection, periodontal disease and oral mucosal disease. Especially for patients who are bedridden for a long time, if the oral hygiene is poor, pathogenic bacteria can multiply and cause serious infection. If there is too much secretion in the mouth, it may even cause aspiration pneumonia by mistake; 3. Observe the oral condition: you can observe the tongue as well as the oral mucosa, assess the oral odor, determine the dynamic changes of the condition, and assist in the diagnosis of related diseases. For example, the possibility of ketoacidosis should be considered when a diabetic patient has an oral odor that tastes like rotten apples.