Kim: Saliva. Body fluid is saliva secreted in the mouth. In traditional health care in China, saliva is extremely precious and has the reputation of life-prolonging syrup. As far as medical knowledge is concerned, saliva contains many beneficial components, especially in promoting digestion and enhancing nutrient absorption. On the one hand, it can quench thirst, on the other hand, it can nourish life. A healthy and energetic person has a lot of saliva in his mouth.

Body fluid: refers to the body fluid of the human body, which is a term of health preservation in traditional Chinese medicine. Its fluid usually refers to the essence secreted by the human body, including semen, digestive juice and sweat. In modern language, it can also be said that the human body needs various digestive enzymes, water, sweat and lymph.