Chinese medicine emphasizes the unity of man and nature as well as that of all the tissues of the body system. Based on the concepts of Yin, Yang, the five elements, and “man-heaven harmony,” it views the human body as “being able to resist the harmful qi pronounced, 'chi.'” Harmful qi is essentially any external element that causes disease, i.e. bacteria or environmental toxins. When the vital qi is inside the body (when the body's systems are in balance and immunity is high)” and “inevitably weak where the harmful qi dominates (unable to fight off disease)”. Emphasis is put on the principles of disease prevention, which allows for a flexible approach in regards to a patient's prevention program. Conclusions regarding the body's internal condition are reached from observing and analyzing the outward appearance of each individual. Thus, Chinese medicine is committed to exploring the secrets of life.

As the basis of longevity, health means the absence of harmful matter and factors inside the body. Nowadays, people can be divided into three categories: the healthy, accounting for 5% of all people, the sick, 15%, and the predominately sub-healthy, at approximately 80%. The sub-healthy are in a dangerous state characterized by the constant presence of hidden damage, which has yet to cause significant inconveniences. Such people need to CLEANSE the spleen, stomach, and intestines, REPLENISH qi, the blood, Yin and Yang, and STRENGTHEN nutrition that is deficient so as to reach the health care goal of BALANCING.

The human body is an organic whole, where an imbalance between Yin and Yang will lead to the malfunctioning of the internal organs. When 1 organ gets damaged, all the others are affected, which results in an imbalance in the human body. Therefore, unfavorable factors should be removed from the body beforehand by restoring balance and strengthening nutrition. As stated above, “the body is able to resist the harmful qi when the vital qi is inside.” When the harmful qi enters the body, the vital qi actively combats it; the subsequent struggle disturbs the balance between Yin and Yang in the body or causes the internal organs to malfunction, which results in the operational disorder of qi and blood reflected by a series of pathological changes. If the vital qi prevails and the harmful qi recedes, the disease tends to improve and be cured. If the vital qi is weak and the harmful qi dominates, the disease tends to worsen and even leads to illness and death.

The above shows how important it is for people to preserve their health on a daily basis. Usually, when one does not have any diseases, she/he easily overlooks the pathological factors hidden in the body and considers himself/herself to be healthy. However, “a huge dam can be ultimately destroyed by seemingly insignificant ant holes.” The body is like that dam, which can only be saved from harm by ridding itself of latent risks beforehand. However, people often only begin to act after they are diagnosed with a disease. As the saying goes, “A three-foot-thick layer of ice is not caused by one day of wintry rigor.” In order to have health that is as strong as ice, one must pay attention to health preservation at regular intervals. Thus one can easily fend off the onslaught of epidemics. How should a person conserve ones health? Everyone needs to understand that because man lives in nature and depends on the interactions of Yin, Yang, and the five elements for his balance with nature, adjustments should be made according to differences in season, region and time zones which meet the individual conditions of the patient. Only in this way can “man-heaven harmony” be realized.

The human body is an integral whole. Nothing can exist without Yin and Yang. As the saying goes, “a single Yin does not grow; a lone Yang does not survive.” The world is an actually integrated as a result of the contradictory unity of Yin and Yang. Yin and Yang represent the properties of matter that are both contradictory and related. Neither man nor nature is separable from the five elements – metal, wood, water, fire, and earth. The property of wood is Yang because it grows and connects. Water is a property of Yin because it flows downward. Fire is attributed to Yang because it goes upward. But Yin and Yang are intermingled. For example, the surface of water is Yang but its bottom is Yin. This explains the integral concept of the contradictory unity of Yin, Yang, and the five elements, which interact with man and nature to form a balance of gain and loss by promoting and restricting each other. In a state of balance, for instance, the body's five internal organs (the liver, heart, spleen, lungs and kidneys) promote each other to make the body strong with a prolonged life. On the other hand, damage to any of the organs will affect all the rest.