Theory of Yin and Yang

Carps - Yin and YangThe concept of Yin and Yang is the most important in Traditional Chinese Medicine (TCM). According to this concept, all phenomena in the entire universe can be classified in two opposites, Yin and Yang, which are part of the same unit. This theory is the foundation of diagnosis and treatment in TCM, together with the theory of the Five Elements.

Yin means: negative, female, passive; north or shady side of a hill; south of a river.

Yang means: positive, male, active; south or sunny side of a hill; north of a river.

Four lows of Yin and Yang

  1. Yin-Yang are opposites and parts of the same unit, like day and night. It is possible to speak of one of the two elements only in relationship with the other.
  2. Yin-Yang are interdependent: they cannot exist without each other. Yin has its roots in Yang, and Yang has its roots in Yin.
  3. Mutual consumption of Yin and Yang: levels of Yin-Yang are continuously changing. Normally a balance is preserved, but when Yin or Yang are out of balance they affect each other, and too much of one can eventually weaken the other.
  4. Inter-transformation of Yin and Yang: one can change into the other. This can occur for example, when there is an excess of one element, so it transforms in the other. That is possible because Yin has a bit of Yang in it (the white dot in the Tai Ji) and vice versa.

Yin and Yang Qualities

Yin-Yang in the universe
Yang Yin
Heaven Earth
Sun Moon
Light Darkness
Fire Water
Time Space
Energy Matter
Activity Rest
Generates Grows
Expansion Contraction
Round Flat
Rising Descending
Above Below
East West
South North
Left Right
Male Female


Yin-Yang and the human body
Yang Yin
Back Front (chest-abdomen)
Head Body
Exterior (skin, muscles) Interior (organs)
Above waist Below waist
Posterior-lateral Anterior-medial
Back and dorsal surface of the limbs Ventral surface of the trunk and limbs
Function Structure
Qi Blood/Body Fluids
Transformation/change Conservation/storage
Small and Large Intestine, Gall Bladder, Stomach, Urinary Bladder Yin Organs: Heart, Lung, Liver, Spleen, Kidney
San Jiao Pericardium

Yin and Yang in Pathology

Clinical signs and symptoms can be interpreted using Yin-Yang theory. When Yin and Yang are in dynamic balance and harmony, there are no symptoms. When Yin and Yang are out of balance, they become separated and a pathology manifests. For example:

when Yin does not cool and nourish Yang, then Yang rises, giving headaches, red face, sore eyes, sore throats, nosebleeds, irritability, ect.

When Yang does not warm and activate Yin, this can cause cold limbs, hypo-activity, poor circulation of blood, pale face, low energy, etc.

Yang Yin
Excess Deficiency
Hyperactivity Hypo-activity
Acute disease/rapid onset Chronic disease/gradual onset
Rapid pathological changes Slowly changing symptoms
Restlessness, insomnia Quiet, lethargy, sleepiness
Throws off bedclothes Wants to be covered
Hot limbs and body Cold limbs and body
Red face Pale face