The Eight Principles: Yin and Yang

by Adam Miramon, L.Ac., Dipl.Ac.
Published: Pathways Magazine, Winter 2014 

Within the practice of Chinese medicine, there are a variety of traditions or schools of thought, and each approaches the preparation of a treatment plan from a slightly different theoretical base. Although each tradition may approach acupuncture or Chinese herbal treatment differently, many of them have a foundation in the Eight Principles. This makes the Eight Principles one of the most prevalent schools of thought in acupuncture and traditional Chinese medicine. The concept of the Eight Principles dates back to one of the original Chinese medical classics – the Huangdi Neijing, which was published between 475-221 BCE. However, the term “Eight Principles” did not appear in medical texts until the Qing dynasty (1644-1912). The basic theory behind the Eight Principles is founded in the following four dualities:


            Yin                                          Yang
            Interior                                  Exterior
            Cold                                        Hot
            Deficiency                             Excess 

This series of articles will provide a basic understanding of the foundations of Chinese medicine by dissecting one conceptual pair at a time. The first pair we will explore is Yin and Yang because they are the most fundamental

Yin and Yang

Yin and Yang are believed to have developed from people’s observations of day and night. This alteration between light and dark led to other observations of cycles between two opposite poles or states of being – one receptive (Yin) and one expressive (Yang).  One of the best ways to understand the concept of Yin and Yang is to look at nature – especially in regions where there are four distinct seasons.

Spring represents Yang within Yin because of the potential for growth. All plant life is giving birth to new leaves and new buds. These buds and leaves represent the potential for the plant during the upcoming year. In Spring, Yang is growing into its fullest potential.

The time that Yang is at its greatest is Summer. This represents Yang within Yang or when Yang is at its maximum. All leaves are in full operation and flowers have become fruit, and the days grow longer. The leaves are working to produce the necessary nutrients for the plant to sustain it through the Winter. This is the time when plants are at their maximum potential.

In Autum, Yin begins to grow within Yang. This is the time when plants extract the nutrients from the leaves allowing them to change color – in effect allowing the leaves to die. The plants lose their leaves and drop their fruit (which carries seeds for new life). These concepts represent the growth of Yin.

Winter brings the greatest expression of Yin. The plants have no leaves or fruit, and the nights grow longer. The weather is cold and several species of animals hibernate. It is as if life in the natural world has slowed to a crawl. Winter represents Yin within Yin.

The abbreviated table below demonstrates some representations of the concepts of Yin and Yang 

            Yin                                           Yang
            Moon                                      Sun
            Rest                                        Activity
            Right                                       Left
            Light                                       Dark
            Cold                                        Warmth
            Grows                                     Generates
            Contract                                 Expand
            Below                                     Above
            Material                                Immaterial
            Descend                                Rise
            Conservation                        Transformation 

Although Yin and Yang are a duality, each contains a part of the other as demonstrated in the example of the four seasons. Another good example of Yin and Yang is in the symbol below. The dark circle within the white area represents Yin within Yang, and the white circle within the dark area represents the Yang within Yin. Yin and Yang do not exist or operate separately from each other, but rather they co-exist and each contains a piece of the other. This symbol demonstrates that there is an interdependent relationship between Yin and Yang – one cannot exist without the other.

Medical Application

In acupuncture and traditional Chinese medicine, Yang is what warms the body and Yin is the body’s cooling system. They work together to maintain a consistent level of balance. If the system falls out of balance, this creates a pathology that could develop into a more serious condition. However, Yin and Yang can be applied to a variety of medical concepts.

The most common application is Interior and Exterior, which are two of the other dualities of the Eight Principles. The concept of Interior and Exterior apply to organ systems as well as Qi. There are Yin organs and Yang organs, but most importantly, there are forms of Qi that are more Yin and some that are more Yang.

If you are beginning to understand the concept of Yin and Yang, you will notice that the Eight Principles are a representation of Yin and Yang in a very general sense. Interior, Deficiency, and Cold are generalizations of Yin, and Exterior, Excess, and Hot are generalizations of Yang.

All symptoms are considered to be an imbalance in Yin and Yang. This makes the theory of Yin and Yang fundamental to the practice of Chinese medicine; however, this duality pair is far too general to produce an accurate diagnosis or create an effective mode of treatment. Yin and Yang need to be integrated with other theoretical foundations before a mode of treatment can be determined. That being said, the following chart provides a very basic breakdown of symptoms that can be categorized as either Yin or Yang:

            Yin                                           Yang

            Chronic condition                Acute condition
            Onset is gradual                  Onset is rapid
            Disease lingers                   Disease changes rapidly
            Cold                                        Heat
            Weak/shallow breathing   Rough breathing
            Pale, profuse urination      Dark, scanty urination
            Loose stools                         Constipation
            Listlessness/Sleepiness   Restlessness/Insomnia
            Cold body/limbs                  Hot body/limbs
            Pale complexion                  Red complexion
            Desires to be covered         Desires to be uncovered
            Desires to curl up                Desires to stretch out
            Desires hot drinks               Desires cold drinks 


There are four pathologies of Yin and Yang – Deficiency of Yin, Deficiency of Yang, Collapse of Yin, and Collapse of Yang. Deficiency of Yin and Yang will be explained in detail when we explore the concept of Deficiency and Excess. Let us focus on the Collapse of Yin and Yang.

A collapse of Yin or Yang is a serious condition that is usually only seen in hospitals, assisted living facilities, and hospice care. These patterns mean that the pathology of Deficiency of Yin or Deficiency of Yang has deteriorated to the point of total collapse. At this point, Yin and Yang are no longer interdependent, but rather, they have separated. When either Yin or Yang collapses, this becomes a possibly fatal condition.

The symptoms of Collapse of Yin or Collapse of Yang are presented in the following chart:

            Yin Collapse                                        Yang Collapse

            profuse perspiration                      profuse oily perspiration
            skin feels hot                                   chilliness
            hot limbs                                          cold limbs
            dry mouth                                        no thirst
            desire to sip cold drinks                 weak breathing
            urinary retention                             frequent and profuse urination
            constipation                                     loose stools or incontinence 

The concepts of Yin and Yang are utilized in many different schools of Chinese medical thought, and they are fundamental to the practice of acupuncture and Chinese herbal medicine. Each represents a polar opposite of a duality – Yin is receptive and Yang is expressive. While the majority of symptoms are rooted in Yin and Yang, these concepts are too broad to produce an exact diagnosis in Chinese medicine. An accurate diagnosis and treatment plan requires additional evaluation tools, such as the Eight Principles.