What springs to mind when you hear the term yin and yang?  An attractive symbol often used in tattoos and jewelry? A useful phrase to describe polar opposites? Or martial arts movies from the eighties, which may or may not star Chuck Norris?

While all the above may be true, the true meaning of the relationship between yin and yang stretches back over 2000 years and still remains at the core of Chinese medicine and Feng shui.

There are many written records about yin and yang, which can be dated back to the Yin Dynasty (about 1400 – 1100 BC) and the Western Zhou Dynasty (1100 – 771 BC). Yin and yang is the basis of Zhou yi (Book of Changes).  Yin and yang became popular during the Spring and Autumn Period (770 – 476 BC) and the Warring States (475 – 221 BC).

While the laws of yin and yang could explain the workings of the universe and have kept keen philosophers occupied for hundreds of years, I am more interested in how Chinese medicine uses yin and yang to diagnose and treat illness.

Yin and Yang is part of the 8 Guiding Principles devised by Zhang Zhong Jing (张仲景) (150—219 AD). Yin pertains to cold, internal, deficiency, blood, while yang pertains to heat, exterior, excess and Qi. All symptoms and the constitution of the body is described in these terms. For instance an elderly person who has oedema in the legs, feels cold and lacks energy has a yin condition. This person lacks yang, so treatment with Chinese herbs and acupuncture emphasizes warming and tonifying the yang.

Fever, redness, restlessness could be classed as yang excess. In western medicine,  fluids and anti-pyretic medications, which are all yin in nature, are prescribed.  In Chinese medicine we use cupping, acupuncture and herbal formulas to cool the blood, remove the toxin and clear excess heat.

It is a matter of returning the body to a balance of yin and yang.

These are two clear cut  examples of yin and yang imbalance. However in reality, most illnesses have a a mixture of symptoms that reflect both yin and yang, such as in diabetes. A diabetic may feel cold and cramping in the legs, but experiences extreme thirst due to internal heat and dryness.  The  formula for such a patient would contain a number of herbs which disperse the internal heat, produce fluids to quench the thirst, and clear the cold stagnation in the legs.  It is fortunate that classical formulas for this condition and many other disorders have been documented, tested for hundreds of years and readily available today.

If you are interested in knowing more about the yin and yang philosophy, I recommend you click here