The Eight Principles

Knowing ‘the eight’ can be a goldmine of diagnoses.

Knowing ‘the eight’ can be a goldmine of diagnoses.


This Gets …

a bit in-depth, slightly technical. If it’s not your cup of tea (this would be quite important in China) please escape to any other link (recommendation: How to Heal) or prepare yourself for some surface-level Chinese medicinal understanding.

Alongside the 5 Elements, Chinese Medicine’s Eight Principles is the other primary means through which a TCM diagnosis is determined. In Chinese Medicine we are always dealing with balance within the body, and as such, balance within the energy of the body (inclusive of the energies acting upon the body: psychological/emotional, physical, or otherwise). The Eight Principles are widely used as a system for categorizing clinical signs and symptoms into specific groupings for the purpose of a diagnostic workup. They are a set of subdivisions, utilizing understanding of Yin and Yang to create clinically relevant subcategories consisting of polar opposites. Each pair of opposites is used in the assessment and diagnosis of a dis-ease state.

The Eight Principles most often occur in a variety of combinations, the usual consisting of one parameter from each pair, as seen below:

  • Interior - Exterior

  • Hot - Cold

  • Excess - Deficiency

  • Yin - Yang*

*Traditionally, only the first six of the Eight Principles are used during the diagnostic work-up, the Yin Yang pair being the energetic component that supports and helps define the initial six polarities.


This pair indicates the location of a dis-ease state. Interior conditions place the site of the dis-ease in the internal organ systems of the Zangfu, as well as any other deep physiological system within the body such as the bones, brain or spinal column. Interior conditions are most often associated with chronic dis-ease patterns. Signs and symptoms such as pain or discomfort in the chest or abdomen, chronic cough, asthma, changes in stool or urine, indigestion, heart issues, diabetes, vomiting, and so on, are examples of typical medical conditions that would (likely) be considered Interior.

Exterior conditions are defined as being located in the skin, muscles, and joints in addition to the meridians that travel along the surface of the body (you would learn about this through curriculum study). Exterior conditions are, traditionally, more acute. A very common presentation is the common cold in which an individual has been invaded by an Exogenous Pathogenic Influence (EPI) - a presence, active, and living inside an organism or living cell, that originated outside the organism. Other medical conditions considered External include skin rashes and other skin disorders, Bell's Palsy, hemiplegia, arthritis, soft tissue injuries, bursitis, carpal tunnel syndrome, eczema, trigeminal neuralgia, and so on.

Patients may present with both an Interior and an Exterior condition, such as when a person has a chronic heart condition and also presents with a cold.


Hot and Cold polarities indicate the temperature of a presenting condition.

Cold, however, can mean different things.

The first: the entire body is simply lacking in warmth, as if an individual had a temperature of 97.8 degrees. This condition could be brought on by malnutrition, aging, or other conditions in which the warming action of Qi (the bodies lifeforce) has become diminished.

The second: a Cold External Factor invades the body resulting in chills and body aches. Generally, when cold is a factor in illness the person will shows signs of slowness, paleness, pain that is lessened with warmth, shivering, and so on.

Hot indicates dis-ease conditions in a state of hyperactivity or inflammation. Signs and symptoms include quick agitated movements, inflammation, redness of the face and/or eyes, fevers, and so on.

The evaluation of Cold/Hot is relatively self-explanatory, however a person may present with both conditions present. For example, a person who has caught a cold and is shivering may also have a condition referred to as inflamed arthritis. Many times individuals will present with neither Cold nor Hot being present. In these cases, this pair of opposites is simply not used in the diagnostic assessment.


The third pair of opposites can be the most difficult to comprehend.

Generally, this pair is distinguished in two manners:

  1. the presence or absence of an Exogenous Factor that is invading the body, or an unnatural accumulation within the body;

  2. the consideration of the relative strength or weakness of the body's inherent energies

In the first case, the presence of an invading factor, or EPI, always indicates an Excess condition. When such an invasion occurs, the appearance of an excess amount of energy is seen to gather in the superficial layers of the body: the EPI itself, and the Wei Qi, which has been stimulated to flourish and fight off the EPI. The other type of Excess is the unnatural accumulation of substances in the body. This would include conditions such as blood clots, edema, swellings, and so on. These will have a greater or lesser effect on the body depending upon the second consideration, the strength and energetic balance of the Qi, Blood, Zangfu ... If energetics of the body are strong, EPI’s will not so easily enter the body and accumulations will not be able to thrive. However, if the body is weakened, the resistance to an EPI invasion will be lessened … the forces that resist accumulations will be compromised. In this regard, combinations of both Excesses and Deficiencies are commonly seen to coexist in clinical practice.