The Influence of Yin-Yang Theory in Traditional Chinese Medicine on Diagnosis and Treatment

The core theory of Traditional Chinese Medicine (TCM) is established on the foundation of Yin-Yang theory. It is believed that Yin and Yang are opposite, mutually restrictive and interdependent in their relationship. Yin-Yang theory deeply influenced not only the core philosophies of Chinese Taoism and Confucianism but also profoundly shaped TCM’s diagnostic and therapeutic approaches. In a word, Yin-Yang theory is “balance”. TCM aims to aid the human body in maintaining or restoring balance or equilibrium, the optimal state for healing and health.

The adept practice of TCM requires understanding of Chinese culture, history, and philosophy. Most notably, physiological functions and pathologies were interpreted in terms of Yin-Yang in the early TCM classic Huangdi neijing (The Yellow Emperor’s Classic of Internal Medicine). The organs, referred to as zang-fu, are divided into Yin and Yang based on their functions. While storage is considered Yin, transformation is Yang. Within each organ, substance is Yin, while function is Yang. The interactions of Yin and Yang within the body constitute one’s physiology.

Four Aspects of the Yin-Yang Relationship

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Opposition: Each opposes the other in its state of being or stage in a cycle. Yin is to cold as Yang is to hot, and Yin is to winter as Yang is to summer. Taking a look at the Yin-Yang symbol, this is evident. The two are at opposite ends of a shade spectrum, Yin being black and Yang being white.
Interdependence: Yin and Yang are both opposite and interdependent. Without one, the other cannot exist. This is symbolized by a dot or seed of Yin in Yang, and vice versa.
Inter-transformation: Nothing is completely Yin or Yang. Rather, they are constantly transforming into one another. Night transforms into day, as winter transforms into spring. In the Yin-Yang symbol, this is shown by the flow of each element into the other.
Mutual restriction/consumption: When out of balance, the dominant element consumes and weakens the other. In balance, the two control each other.

Mutual Restriction of Yin and Yang, and Balance

A healthy physical condition refers to the relative balance of Yin and Yang within and between the various organs of the body. Alone, the human body has self-regulating functions and self-healing abilities. Various factors such as stress, emotions, diet, lifestyle habits, climate, environment, and invasion of harmful pathogens can cause varying degrees of Yin-Yang imbalance in the body. Due to differences in individual repair and regulatory functions, some can self-regulate and recover, while others may develop pathology beyond self-repair capabilities. Then, professional intervention is required to restore relative balance through medical treatment. Such differences occur between the elderly and the young, or between weak and strong individuals, and in the degree of influence of imbalancing factors.

In TCM treatment, the first focus is on diagnosis. In TCM diagnosis, the classification of Yin and Yang is essential. At the forefront are the Four Diagnostic Methods: observation, auscultation, interrogation, and palpation (including pulse examination). The attributes of a disease are uncovered by observing complexion, physique, and demeanor, listening to voice and breath sounds, inquiring about medical history and symptoms, and taking pulse diagnosis. Said attributes can then be categorized into eight cardinal principles. Of the eight major aspects of clinical diagnosis in TCM, Yin-Yang constitutes the first two aspects. The remaining six are derivatives of Yin and Yang. For instance, discerning whether the patient’s condition leans towards Yin or Yang is crucial, reflected in symptoms like coldness (Yin) or heat (Yang), deficiency (Yin), or excess (Yang), interior (Yin) or exterior (Yang). This differentiation is distinct from Western medicine’s diagnostic standards, which rely heavily on scientific or empirical data.

The patient’s problem must first be identified as yin or yang: whether interior (Yin) or superficial (Yang), cold (Yin) or heat (Yang), deficiency (Yin) or excess (Yang). In this way, classification of Yin-Yang guides the treatment. The principle of opposition applies – using cooling medicine for heat syndrome, and warming medicine for cold syndrome. From here, we can explore the causes of these Yin and Yang imbalances in more detail. Causes include external pathogens, internal factors, excessive cold, excessive heat, phlegm dampness, blood stasis, external injury, and organ-specific imbalance.

The theory of Yin and Yang balance can also guide the treatment of individuals who have not yet developed pathology but show signs of Yin-Yang imbalance. This is the difference between TCM treatment and Western medical treatment. Western medicine is characterized by a scientifically rigorous set of diagnostic standards. Laboratory data is mainly used to confirm and diagnose disease before treatment methods are secured. On the other hand, Chinese medicine mainly relies on syndrome differentiation (Bian Zheng) from the aforementioned Four Diagnostic Methods. This includes both cases of disease and non-disease.

Imbalance of yin and yang can exist in the human body in the absence of disease. For example: some young people always feel that their hands and feet are cold, their memory has deteriorated, have difficulty concentrating, and have decreased libido. These people may not be called sick because their laboratory indicators are normal. However, traditional Chinese medicine can diagnose such patients with Kidney Yang deficiency. Treatment principles would be oriented toward replenishing Kidney Yang. Possible prescription of herbal remedies include Jin Gui Shen Qi Pills, You Gui Pills, and the like, with capabilities to replenish Kidney Yang. By strengthening one side (yang) to restrict the other (yin), “yin will replenish yang, and yang will nourish yin” when balance is reached. This illustrates the relationship of mutual restriction. Using the theory of Yin-Yang balance, the TCM practitioner can intervene in advance before disease is formed. Prevention is what TCM teaches – the capability of the TCM practitioner to treat disease before it comes is arguably the most valuable of Chinese medicine and a major boon for the public’s acceptance of Chinese medicine.

In contrast, the following example illustrates the use of Yin-Yang theory in the diagnosis and treatment of one who is already ill. For a mental patient, one must first understand and observe the nature of their symptoms: whether they are silent and less reactive (Yin syndrome) or manic, hyperactive and talkative (Yang syndrome), and then by observing his or her face color (Yin = pale, Yang = red), tongue color (Yin = pale white, Yang = crimson), pulse (Yin = deep and thin, Yang = fast and strong), and other means to understand specifically which imbalances in the organs caused the disease. Is it a deficiency of Yin, or is it an excess of Yang? Excess of Yin, or deficiency of Yang? With clear diagnosis, the treatment will have its direction. With the right direction, even though each doctor uses different treatment methods and produces different effects, there will be no significant mistakes. Following this example, symptoms of mania (animation belonging to Yang and fire) can be controlled thus. When Yang exceeds Yin, one can try the Zhen Shi Gun Tan Decoction. Among its ingredients, Da Huang is a cool medicine (Yin) that directly purges the fire (Yang). Jinzhenshi treats the source of fire: phlegm condenses and blocks, obstruction generates heat, and extreme heat generates fire. It is like extinguishing a fire. One herb takes away the things that started the fire, and the other pours water. Once the metaphorical fire is extinguished, the symptoms are initially relieved. Then, according to the patient’s subsequent Yin-Yang changes, the method of calming the nerves (Yin) and nourishing Yin is used to further control or even cure the condition.

On the contrary, diseases that cause the patient to be silent and less responsive (quietness belonging to Yin), necessitate the raising and replenishing of Yang as well as to help Yang flow normally. Therefore, the treatment is based on approaches and herbs that promote Yang and relieve depression. First, there is Chai Hu Long Gu Mu Li, the main medicine of which is Gui Zhi, hot in nature. Although Chai Hu is slightly cold, it has the effect of relieving depression and promoting Yang. Secondly, Jin Gui Shen Qi pills (Fu Zi and Rou Gui are both hot medicines and belong to Yang) can nourish kidney yang. Third, to remove blood stasis, Xue Fu Zhu Yu pills can be employed (which promote the movement of Qi and Blood, Qi belonging to yang). Lastly, to replenish Heart Qi, one can use Gan Mai Da Zao pills, again increasing Yang to control Yin. These prepared formulas can be used alone or mixed according to the diagnosis of the disease. Of course, to be more effective, specific prescriptions can be formulated based on this concept and better accounting for the patient’s personal physical characteristics.

Interdependence of Yin and Yang

Interdependence refers to how Yin and Yang are both conditions for each other’s existence. For example, without Blood (Yin), Qi (Yang) cannot be maintained, and without Qi, Blood cannot be generated. Long-term severe Qi deficiency will inevitably affect blood deficiency, and long-term severe Yin deficiency will lead to Yang deficiency. This theory guides us not to overlook Qi supplementation when treating extreme blood deficiency, and vice versa. A formula that illustrates this perfectly is Da Bu Xue Decoction, for severe blood deficiency. A large amount of Huang Qi is for nourishing Qi (Yang). Secondly, Dang Gui is for nourishing Blood (Yin).

When treating imbalance between organs in TCM, one should not nourish Yang and neglect to concurrently nourish Yin. Again, we may analyze Jin Gui Shen Qi Wan. This prescription is for tonifying Kidney Yang. Among its herbs, hot Fu Zi and Gui Zhi are combined with the ingredients of the fundamental prescription for nourishing Yin (Liu Wei Di Huang). Similarly, in treating organ imbalances, balancing Yang without neglecting Yin is essential.

The interdependent relationship between Yin-Yang may be described as such: Yin is the biochemical spring of Yang. Yang is the driving force of Yin. In other words: “Lone Yin does not prosper, lone Yang does not grow” (Liu Wansu’s theory). This theory is of great significance especially in treatment prescriptions. It is reflected in the herbal roles in a prescription: monarch, minister, adjuvant, and envoy. Practical example: a patient diagnosed with Wind-Heat affliction could not stop coughing. He first went to see a Western doctor and was given antibiotics and cough medicine, to little relief. One TCM doctor prescribed an herbal formula, which also yielded little effect. Later, another TCM doctor added 3 grams of raw Ma Huang (Yang) to the initial formula. Surprisingly, after taking one dose, the symptoms improved, and after the second dose, the patient was completely cured. Why? The antibiotics initially and the prescriptions of traditional Chinese medicine for clearing away heat and detoxifying are both cooling (Yin). Although these cold medicines suppress the heat (Yang), Lung Qi needed to be released. The cold medicines suppressed lung qi, making pathological phlegm unable to be discharged. This also resulted in the patient being unable to be cured. The Da Huang that was later added has hot properties and can induce sweating and dissipate cold. When used in small amounts, it produces no sweating effect but has the effect of dispersing cold and releasing Lung Qi. Its use in a small amount cleared away heat and detoxified without suppressing Lung Qi, resolving the Wind-Heat and allowing phlegm to be released. Therefore, when prescribing, a good TCM doctor will add one or two herbs with opposite properties to the majority of main herbs to reduce side effects and enhance the efficacy of the medicine. In the same prescription, there will be a main medicine and a medicine with the opposite direction. This is the guiding role of the theory of Yin-Yang interdependence in TCM treatment. The diagnosis and treatment principles of TCM are inseparable from the basic theory of TCM. The theory of Yin and Yang holds critical guiding significance in the diagnosis and treatment of diseases and especially in their prevention. Again, preventing the occurrence of diseases is a unique advantage of TCM. Furthermore, TCM recognizes and can relieve complaints in the absence of disease.

Yin-Yang Guiding Disease Prevention

As TCM physicians, we can use the relationship between Yin and Yang to educate TCM patients.

Patients should know how to maintain inner body balance. Relevant advice includes avoidance of overeating or eating food that is too cold or too hot (excessive coolness damages yang, excessive heat damages yin).
The patient should balance stillness (Yin) and movement (Yang). Excess of either rest or working can cause an imbalance of Yin and Yang.
The patient should pursue appropriate exercise according to individual age and physique.
The ideal mental environment should be calm.
The patient should be wary of drinking and smoking. Chronic drinking upsets theLiver and Stomach Yin. As a result, Liver fire and Heart fire (Yang) cannot be controlled by Yin, resulting in hyperactivity of Liver fire (i.e. high blood pressure) and inflammation of Heart fire (i.e. palpitations, anxiety…). Long-term smoking damages Lung Yin, eventually leading to frequent dry coughs.

Conclusion

The diagnosis and treatment in TCM are inseparable from its fundamental theories, and the theory of Yin and Yang plays a crucial role. It embodies the essence of ancient Chinese philosophical thought and is particularly valuable in preventive medicine, addressing imbalances before they manifest as diseases. This unique aspect of TCM allows for early intervention, supplemented by educating patients on how to maintain internal balance through lifestyle adjustments tailored to individual needs. A practitioner’s proper understanding and application of Yin-Yang theory leads to better treatment outcomes, ultimately promoting acceptance and appreciation for TCM treatments.

References

Internet Encyclopedia of Philosophy. (n.d.). Yin-Yang. In Internet Encyclopedia of Philosophy. Retrieved March 31, 2024, from https://iep.utm.edu/yinyang/