What Are Yin and Yang in Chinese Medicine?

what-are-yin-and-yangThe concepts of Yin and Yang serve as the foundation of traditional Chinese medicine (TCM). The earliest reference to Yin and Yang is approximately 700 B.C.E. in an ancient text called I Ching, according to the Traditional Chinese Medicine World FoundationYin and Yan theory — considered the most important in TCM — drives the understanding of health and wellness among practitioners of this ancient system of health care. The theory informs how diagnoses are made, and underpins the physiology, pathology and treatment of illness. It is an important part of the study of TCM.

The qualities of Yin and Yang

Ancient scholars observed two phases of constant and cyclical change. They described it this way: Yin changes into Yang, and Yang changes back into Yin. A few general qualities of Yin and Yang help illustrate the concept. 

Yin: Cool, rest, moist, earth, dark

Yang: Warm, active, dry, sky, bright

Yin and Yang represent opposite but complementary qualities. Notice how Yin has a component of Yang, and Yang has a component of Yin. This is represented by the dots in a Yin-Yang symbol. The TCM World Foundation describes it further:

"Like Einstein’s famous equation, E = mc², the Yin-Yang symbol describes something very elemental and incredibly complex. What Yin-Yang points to and represents is so vast it encompasses everything in the Universe."

Each object, person or phenomenon you encounter in the world is itself and also its contrary, according to TCM. In other words, everything in the universe encompasses Yin and Yang at the same time. This concept lies at the heart of TCM philosophy.

The four aspects of Yin and Yang

To more fully comprehend the concepts of Yin and Yang, it helps to explore how the two relate to and play off each other. These dynamics are considered the four aspects of Yin and Yang. They are:

  1. The opposition of Yin and Yang
  2. The interdependence of Yin and Yang
  3. The mutual consumption of Yin and Yang
  4. The inter-transformation of Yin and Yang

Yin and Yang cannot exist without each other — they are inseparable. Yet they are also constantly consuming, or becoming, one another, just as day becomes night and vice versa. Think about it this way also: the way night and day blend into each is seamless. Together day and night make a whole.

The correspondences of Yin and Yang


To further explore the concepts of Yin and Yang in TCM, consider some of the pairs, or correspondences, that represent each side of these two universal energies:

Yin, Yang

Female, Male

Right, Left

West, East

North, South

Earth, Heaven

Moon, Sun

Space, Time

Matter, Energy

Darkness, Light

Water, Fire


Rest, Activity

Grows, Generates

Contraction, Expansion

Flat, Round

Descending, Rising

Below, Above

All phenomena in the universe are the result of the interplay between Yin and Yang. Every phenomenon contains within itself both aspects in different degrees of manifestation. In its purest form, Yang is totally immaterial and corresponds to pure energy. On the other hand, Yin, in its coarsest and densest form, is totally material and corresponds to matter. Energy and matter are but two states of a continuum, with an infinite possible number of states of aggregation.

Understanding the concepts of Yin and Yang are fundamental to the study of traditional Chinese medicine. To learn more about the Oriental Medicine program at Acupuncture and Massage College, email the admissions department.


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