Yin and Yang Theory
 
In Nature there are two equal and opposite forces, for instance, Sun and Moon, Men and Women, Day and Night, Heat and Cold etc. Balance among these forces is essential. The same principle applies to our human body as it is part of nature. The two energies consist of Yin (negative) and Yang (positive) which are in balanced state in a healthy person. Whenever there is an obstruction to the flow of energy or when there is deficiency or excess of energy in a particular organ or if there is imbalance between yin and yang factors, the person falls sick. By using acupuncture needling, these obstructions can be corrected.

Zang-Fu Theory

There are two categories of the organs associated with 12 organ meridians called Zang organs and Fu organs. Zang organs are negative and solid organs having storage functions. While fu organs are positive and hollow organs having eliminative functions.

TRADITIONAL LAWS OF ACUPUNCTURE

1.Mother-Son Law
2.Midday-Midnight Law
3.Husband-Wife Law
4.Theory of Five Elements
 
These laws are a consideration of living interdependent dynamism of the body.

Mother-Son Law
 
If the lung meridian is empty, one should tone its mother, the liver. If the lung is full, one should disperse its child, the  large intestines. Mother-Son law can be applied to the law of five elements also. Thus if the lung meridian is empty, one should tone its mother, the spleen and if lung is full, one should disperse its child, the kidney. Thus there are two alternative routes.

Midday-Midnight Law
 
Chinese people believe that each of the twelve organ-meridian-function complex has a period of two hours during which its activity becomes maximum. Chinese took therapeutic advantage of this. Thus the liver has maximum activity from 1 A.M. to 3 A.M. and so any type of physiological, embryological or anatomical entities which occur  during this period are grouped under liver . For e.g. Liver type of migraine. 

This law can be used for diagnosis also. If a meridian is deficient, it should be treated during the period of maximum activity. If the meridian has excess, it should be treated after the period of maximum activity.

Husband-Wife Law
 
This traditional Chinese law is based on the principle of pulse diagnosis. They believe that the disorders of the internal organs can be detected by the various pulse positions of both the wrists. 

Pulse are of two types-superficial and deep. In each wrist there are three superficial and three deep pulse, making it twelve pulse in both the wrists for the twelve internal organs of the body. The superficial pulse are of Yang in nature whereas deep pulse are Yin in nature.

Moreover it is said that the pulse of left wrist are husband in type and pulse of right wrist are wife in type. As husband dominates wife, the pulse of left wrist dominates the pulse of right wrist. The pulse related to the husband are-kidney, urinary bladder, liver, gall bladder, heart and small intestine. The pulse associated with the wife are pericardium, triple warmer, spleen, stomach, lungs  and large intestines.

Theory of Five Elements

The traditional Chinese philosophy believes that the universe is basically made of five "elements" viz. wood, fire, earth metal, and water. A man is also a part of nature and hence he is also thought to be comprised of' the five "elements" of the universe. 

In nature nothing exists as a single form and separated from the other, indeed there is always some influence of one over the other in such a way that it becomes predominant. In Yin and Yang principle, Yin or Yang never exists separately but there is always some Yin component in Yang and Yang component in Yin. Similarly the five elements cannot be separated from one another in a single subject but the nature of the subject depends on the predominance of the particular element.
 
The traditional Chinese medicine classified all the  internal organs of the body into two groups-"Yang" (Hollow) organs and "Yin" (Solid) organs and accordingly, a particular "Yin" organ and a particular "Yang" organ  unite to fall in the regulation of universal law (couple organ). 

In other words,  a particular Yin and Yang organ are related to a particular element of the universe. The five elements interact with each other to form a constructive or generative (Sheng) cycle or interact in a destructive way to form a destructive (Ko) cycle. 

The "Qi" energy circulates among the different elements of the universe to stabilize them and similarly it circulates in human body to make a balanced state (healthy). Any exogenous factor (hot, cold, humidity, virus, bacteria etc.) or endogenous factor (sorrow, fear, anger, shock etc.) may block the flow of vital energy and subsequently the body is  diseased.