Traditional Chinese Medicine (TCM) approaches dynamic balance in a way different from Western medicine.
2.3. TCM Based on Yellow Emperor’s Canons of Internal Medicines
As one can clearly see, Yin and Yang are always in constant dynamic motion maintained by a continuous adjustment of the relative levels of Yin and Yang. When either Yin or Yang are out of balance, they naturally affect each other and change their proportions to achieve a new balance. And there are four possible ways in which a Yin-Yang imbalance can occur as illustrated in the diagram below:
1) Preponderance or Dominance of Yin
When Yin is excessive, it induces the decrease of Yang and it also means that the Yin consumes Yang.
2) Preponderance of Yang
When Yang is excessive, it induces the decrease of Yin and it also means that Yang consumes Yin.
3) Weaknesses of Yin
When Yin is weak, Yang will be seen in apparent excess. This apparent excess is only in relation to the deficient quality of Yin.
4) Weaknesses of Yang
When Yang is weak, Yin will be seen in apparent excess. Similarly, this apparent excess is only in relation to the deficient quality of Yang.
Therefore, in these illustrations, it is very critical to be able to see the differences between the two states: the preponderance of Yin and the weakness of Yang. This is because on one state it is the truly excess Yin and on the other state it is the weakness of Yang that Yin is seen as apparent excess. Similarly, this differentiation applies between the preponderance of Yang and the weakness of Yin. 
-  G. Maciocia, “The Foundation of Chinese Medicine: A Comprehensive Text for Acupuncturists and Herbalist,” Churchill Livingston, London, 1989.
It can be said that the theory of Yin and Yang is fundamental in Traditional Chinese Medicine (TCM) and every physiological process and every symptom or sign of a human body can be analyzed in the light of the Yin-Yang theory. In other words, TCM sees illness as an imbalance in the patient’s whole system. It tries to get to the underlying root cause of a health problem. The aim is to heal the person’s mind, body and spirit rather than just his or her sore throat or stomach ache.  Ultimately every treatment modality is aimed at 1) improving Yang, 2) improving Yin, 3) reducing excess Yang and reducing excess Yin, and understanding the application of the theory of Yin-Yang theory is of great importance.
Source: P. Low and S. Ang, “The Foundation of Traditional Chinese Medicine,” Chinese Medicine , Vol. 1 No. 3, 2010, pp. 84-90. doi: 10.4236/cm.2010.13016. Also cached at https://www.researchgate.net/publication/235933675_The_Foundation_of_Traditional_Chinese_Medicine