One of the central features of traditional Chinese medicine is the analysis of diseases and their treatment in terms of the five zang (often translated as viscera, solid organs, or internal organs). That there are five internal organs that represent the focus of this medical system is a reflection of traditional reliance on the five elements concept. The concept of yin and yang, the other basis for Chinese medicine, is reflected in the depiction of pairs of internal organs: for each zang, there is a fu (often described as hollow organs) and the complete system is described as zangfu .

The term "organ networks" is utilized here to indicate that Chinese physicians were not interested in the organs as physical objects, but as extended networks functioning throughout the body. In modern medicine, it is common to look at the internal organs as individual physical units, subject to inspection and surgical removal (in part or in whole). By contrast, the Chinese system was developed by considering the person as a whole and by relying on what is visible or palpable at the surface. The Chinese organ networks were described in nearly complete absence of surgery .

In classical Chinese medicine, detailed knowledge of the dynamics and interrelationship of the five organ networks is considered the foundation for successful practice. This system of knowledge describes the body as a dynamic system of intertwined functional circuits that reflect and resonate with the macrocosm of the universe.

Unfortunately, the traditional view of the organs is made difficult to understand by the fact that organs known to modern medicine have been directly linked, by naming, to those of traditional medicine, as follows:

As a result of this linkage, the gan "rectifying system," traditionally defined by its function of regulating the upward and outward expansion of qi and blood, is now labeled with the same term, liver, as the anatomical organ that is known, almost exclusively, for its metabolism of biochemicals. In Chinese, both the traditional organ network and the anatomical organ are called "gan," and in English, both are called "liver."

The five organ network approach presented here owes much to the teachings and inspiration of Professors Deng Zhongjia and Zhou Xuexi of the Chengdu University of Traditional Chinese Medicine. Dr. Deng is the University's Dean of Fundamental Studies, and is a prominent voice calling for the restoration of a Chinese medicine education that is anchored in the classics. Professor Zhou is one of the few remaining elders of the field. He is one of China's leading authorities on studying the connection between ancient Chinese philosophy and traditional Chinese medicine. To further this cause, he has written two influential books, The Science of Change: Root Theory of Chinese Medicine (Zhongguo Yi Yi Xue) and The Five Organ Networks of Chinese Medicine and Their Pathology (Zhongyi Wuzang Bing Xue).

The bulk of the presentation of the five organ networks-which is in outline form-features the definitions that appear in the root classics of Chinese medicine, especially the Huangdi Neijing (The Yellow Emperor's Classic of Medicine). These statements are accompanied by the remarks of traditional commentators who tried to illuminate the terse Neijing style. Each organ network web page consists of the following five parts:

1. Traditional Commentaries: Translations of selected texts about the network in question. Many of the statements contained in the Neijing are extremely brief, crafted during a time when the art of complex writing was still in its formative stages. The enigmatic character of the Neijing has prompted generations of medical scholars to interpret the five organ networks and other fundamental concepts of Chinese medicine in the context of their time. The commentaries presented here are only a small selection from scores of extant medical literature on the subject (see below for list of major sources). Most of them were chosen for their individual insight into particular aspects of an organ network, while others were selected to illustrate the strong bias that certain scholars, schools, and even entire eras of Chinese medicine held with respect to the importance of a particular organ network.
2. Network Functions: A compilation of statements defining the functional characteristics of each network, mainly from the Neijing Suwen (Simple Questions) and the Lingshu (Magical Secrets, often translated as Spiritual Pivot), the second part of the Neijing. These definitions are accompanied by explanations drawn from both ancient and modern source texts of Chinese medicine. The Neijing definitions presented here are the core of five organ network theory. They have been quoted by Chinese medicine scholars over the span of two millennia and continue to form the basis of modern textbook presentations. Most standardized TCM texts, however, do not list the classic definitions in their entirety and lack a comprehensive analysis of the inherent information.
3. Etiology and Pathogenesis: A brief outline of the pathological tendencies of the network, followed by a list of specific pathological scenarios. This section is designed as a stepping stone connecting the important topics of network physiology and network disease patterns. It aims at helping the reader understand how network pathology is primarily the result of a malfunction of one or several of the network's physiological characteristics that were introduced earlier.
4. Therapeutic Guidelines: An introduction to the general treatment principles that apply to each network, based on its physiological functions and elemental characteristics. Since much has been written on the therapeutic principles of acupuncture, this section focuses on guidelines for herbal approaches.
5. Typical Disease Patterns: A presentation of common disease patterns mentioned in both traditional and modern textbooks. The patterns listed here primarily follow the format of Professor Zhou's book, The Five Organ Networks of Chinese Medicine and Their Pathology. The headings within this section represent the actual terms in which a Chinese medicine practitioner would phrase the diagnosis. They are listed in order of importance, and the ones most typical for a particular network are at the beginning of the section. A listing of representative herbs and formulas has also been included in this section.

Texts predating or contemporary with the Neijing and texts that contain quotes from that period (Warring States, Qin Dynasty, Han Dynasty):

Guanzi, prior to 200 B.C.
Contemplations by the Huainan Masters (Huainanzi), ca. 110 B.C.
The Hidden Dao: A Collection (Daozang), the prolific Ming dynasty compilation (ca. 1600) of esoteric Daoist texts, some of them dating back to 600 B.C.
The Original Classic of Guiding the Breath (Daoyin Benjing), ca. 100 B.C.

Texts written prior to or during the Ming Dynasty (which ended in 1644 A.D.), during the great revival period of traditional Chinese medicine:

Li Dongyuan, Illuminating the Science of Medicine (Yixue Faming), ca. 1240.
Li Dongyuan, A Treatise on the Spleen and Stomach (Piwei Lun), 1247.
Yu Bian, Medical Teachings Continued (Xu Yishuo), 1522.
Li Ting, A Primer of Medicine (Yixue Rumen), 1575.
Sun Yikui, Mysterious Pearls of Wisdom by Chi Shui (Chi Shui Xuan Zhu), 1584.
Sun Yikui, Contemplations On Unexplored Medical Topics (Yizhi Xuyu), 1584.
Wang Kentang and Wu Mianxue, The Compendium of Traditional Diagnosis (Gu Jin Yitong Zhengmai Quanshu), 1601.
Yang Jizhou, The Great Compendium of Acupuncture and Moxibustion (Zhenjiu Dacheng), 1591.
Li Yuheng, Unfolding the Mat With Enlightening Words (Tuipeng Wuyu), 1570.
Zhuang Yuanchen, Shujuzi: Inner Chapters (Shujuzi Neipian), Ming Dynasty.
Zhang Huang, A Compendium of Illustrated Texts (Tushu Bian), Ming Dynasty.
Li Zhongzi, A Primer of Medical Objectives (Yizong Bidu), 1637.

Texts of the Qing Dynasty (which ended in 1911), during the time when Western medicine was first encountering Chinese medicine, but having little influence, though Chinese medicine was, overall, in a state of decline:

Yu Chang, The Statutes of Medicine (Yimen Falü), 1658.
Chen Shiduo, A Secret Manual from the Stone Chamber (Shishi Milu), ca. 1690.
Ye Tianshi, A Handbook of Clinical Case Histories (Linzheng Zhinan Yian), 1746.
Shen Jin'ao, Illuminating Lantern on the Origins of Complex Diseases (Zabing Yuanliu Xizhu), ca. 1770.
Shen Jin'ao, Dr. Shen's Compendium of Honoring Life (Shen Shi Zunsheng Shu), 1773.
Chen Nianzu, The Three Character Classic of Medicine (Yixue Sanzi Jing), ca. 1810.
Cheng Wenyou, Quotes from Medicine (Yishu), 1826.
Zhou Xuehai, Reflections Upon Reading the Medical Classics (Du Yi Suibi), ca. 1895.

Texts written during the late 19th century and early 20th century period integrating Chinese and Western Medicine:

Tang Zonghai, A Treatise on Blood Disorders (Xuezheng Lun), 1884.
Tang Zonghai, A Refined Interpretation of the Medical Classics (Yijing Jingyi), 1892.
Zhang Shanlei, A Revised Edition of Master Zhang's Treatise on the Organ Networks (Zhang Shi Zangfu Yaoshi Buzheng), ca. 1918.
Zhang Xichun, Chinese at Heart But Western Where Appropriate: Essays Investigating an Integrated Form of Medicine (Yixue Zhong Zhong Can Xi Lu), 1933.
Cai Luxian, Chinese Medicine and Pharmacology: A Collection (Zhongguo Yiyao Huihai), 1936.

The following are examples of quotes from the various texts, one selected for each organ network:

Liver: The liver marks the beginning of cyclical action, the stirring of spring yang which all living things rely upon as a catalyst for their growth. By avoiding outbursts of anger and by fostering this particular type of yang energy, your prenatal qi will keep generating forever. The liver is also in charge of color; if its qi is in harmony, the body will exhibit a healthy luster. If its qi is injured, the body will appear dry and brittle. Nourishing the liver, therefore, first of all means to refrain from anger. This is the key for the maintenance of good health.

Heart: The ancient book of definitions [Neijing] refers to the heart as the ruler of the human body, the seat of consciousness and intelligence. If we decide to nourish this crucial element in our daily practice, then our lives will be long, healthy, and secure. If the ruler's vision becomes distracted and unclear, however, the path will become congested, and severe harm to the material body will result. If we lead lives that are centered around distracting thoughts and activities, harmful consequences will result. The sage regards his body like a country: the heart is the ruler, and the jing and the qi are the citizens. If the heart does not abuse its superior position, if it remains centered and focused on the essential matters, the jing will flourish and the qi will be steady, noxious intruders will always be fought off, the dantian will be full with treasures, and every part of the body landscape will be light and at peace.

Spleen: If we regulate our daily lives by adjusting them to the prevailing energy of the seasons, if we avoid exposure to extreme cold and extreme heat, if we eat and drink in regular intervals, if we protect our shen by avoiding states of extreme anger or extreme ecstasy, and if we strive for balance by living in moderation during all four seasons, there will be peace. Otherwise, the spleen and stomach will suffer harm, and our true qi will leak downward in trickles or currents, with the possibility of failing to rise again. This, then, would be like having autumn and winter but no spring and summer, and a situation would arise in which the functions of birth and growth are muffled by the qi of death and extinction.

Lung: The lung is the lid of the five organ networks. It produces the voice, and it provides proper moisturization to the skin. As soon as there is either internal damage due to the seven harmful emotions, or external injury due to the six climatic influences, the rhythmical process of inhaling and exhaling and the general qi flow between the body's inside and outside are disturbed; the lung metal then loses its clear quality. If we want to restore purity in the metal, we must first strive to regulate the breath. Once the breath is regulated, erratic movement will not occur and the heart fire will calm down all by itself.

Kidney: Everything between heaven and earth that is made from qi and blood has the urge to mate. Once fire and water separate and desire finds a match, the essence leaves the source, and what creates the body will turn into what kills the body. If you are a student of the Book of Change (Yijing) and align your desires by fooling around with the lofty hexagram 41 [Sacrifice, Decrease], then this is like being worried about floods at one moment and about water leakage the next-you 'sacrifice' again and again, thus using yourself up until there is nothing left to spare. Therefore, if you want to protect your source of longevity, there is no better way than to guard yourself against sexual desires.

The sentiments offered by the authors of each of the above quotations differ from that which is presented in modern textbook form, with simple listing of the properties of each organ, the categories of pathological processes, the signs and symptoms, and the remedies that have been offered. These earlier statements are more about self-healing--controlling one's emotions, behavior, and breathing-than about selecting certain herbs, herbal formulas, or, as appear in other texts, acupuncture points and point formulations. Instead of focusing specifically on treating disease, they speak to the issue of preventing disease, or, at the least, preventing disease from becoming worse so that one has a chance to recover health. Prevention through harmonization with nature and balance within the body has been one of the original attractions that Chinese medicine offered to Westerners.