Within the practice of Eastern medicine, there are a variety of traditions or schools of thought, and each approaches the preparation of a diagnosis and treatment plan from a slightly different theoretical base. Although each tradition may approach acupuncture or Chinese herbal treatment differently, many of them have a foundation in the Eight Principles. This makes the Eight Principles one of the most prevalent schools of thought in acupuncture and Eastern medicine.
Table of Contents
History of the Eight Principles
The concept of the Eight Principles dates back to one of the original Chinese medical classics – the Huangdi Neijing, which was published between 475-221 BCE. However, the term “Eight Principles” did not appear in medical texts until the Qing dynasty (1644-1912). The basic theory behind the Eight Principles is founded in the following eight dualities:
Meaning Through Context
The Eight Principles are meant to be interpreted together as a whole, and this creates a difficulty in attempting to explain parts separately. It’s important to understand that the purpose of these articles is to empower the reader with the knowledge to understand terminology being used by their acupuncturist or Eastern medical professional. The symptoms, diagnoses and examples presented in these articles are in no way a replacement for the expertise of a licensed acupuncturist or Eastern medical practitioner.
Excess and Deficiency
While Interior and Exterior refer to the location of a disorder in Eastern medicine, Excess and Deficiency are indicators of the nature of the condition. A condition can be Excess, Deficient, or a combination of both Excess and Deficiency.
In order to understand Excess and Deficiency, we must first define two terms: Zheng Qi (pronounced jung chee) and Xie Qi (pronounced she eh chee).
Zheng Qi
Zheng Qi includes all forms of Qi and Blood, and it is used to defend the body against pathogenic influences.
Xie Qi
Xie Qi refers to pathogenic factors that may attack the body or Zheng Qi. Therefore, Xie Qi and Zheng Qi are considered to be opposing forces that interact with one another.
Excess Conditions
An Excess condition is one in which Xie Qi (a pathogenic factor) is present in an individual’s system, and the individual’s Zheng Qi is considered undamaged and intact. The pathogenic factor can be internal or external, but there is always one present in an Excess condition.
In Eastern medicine, this condition is labeled shi. Severe or intense symptoms are manifestations of Excess conditions, and this type of condition can be either acute or chronic. One example of an acute, Exterior, Excess condition would be a head cold with sinus congestion, and one example of an acute, Interior, Excess condition would be a migraine headache.
Deficiency Conditions
A Deficiency condition does not have the presence of a pathogenic factor (Xie Qi), but rather is a weakness in the individual’s Zheng Qi. Deficiency conditions do not have the presence of a pathogenic factor, but rather is a description of an individual’s constitution.
Deficiency conditions are labeled xu in Eastern medicine. The symptoms of a Deficiency condition are not as severe as those of an Excess condition. Deficiency conditions can be either acute or chronic; however, most Deficiency conditions tend to be chronic and develop over time.
- An example of a chronic, Interior, Deficiency condition is one in which an individual suffers fatigue due to years of irregular eating.
- An example of an acute, Interior, Deficiency condition would be severe fatigue due to a recent severe loss of blood.
Excess/Deficiency Conditions
There are conditions that are defined as having both an Excess quality as well as a Deficiency quality. These Excess/Deficiency conditions are a combination of the presence of Xie Qi (pathogenic factor) and a deficiency of the Zheng Qi.
In these types of conditions, the body is either unsuccessful or incapable of fighting off the pathogenic factor. A common example of an Excess/Deficiency condition is an individual who is suffering from fatigue following a viral infection, and their system is still attempting to fight off the virus. The result is a chronic condition in which the person neither gets better nor gets worse.
Medical Application
The medical application of Excess and Deficiency is useful in determining the nature of an illness. In the most basic terms, Excess and Deficiency are used to establish whether the illness is caused by an internal or external pathogen, by a weakness of the body, or by a combination of the two.
Although it can be challenging to generalize symptoms, the following chart provides a breakdown of symptoms that are considered either Excess or Deficiency. Conditions that are both Excess and Deficiency do not have a specific set of general symptoms. However, Excess/Deficiency conditions may present with symptoms from either or both categories.
| Excess Acute onset Restlessness Irritability Strong Voice Coarse Breathing Tinnitus – high pitch Scanty urination Constipation Pain that worsens with pressure | Deficiency Gradual onset Tiredness Loose stools Weak voice Desire to rest |
Excess conditions will always involve a pathogen and may contain additional symptoms not noted in this list. Whereas, Deficiency conditions can affect any number of body substances — Qi, Yin, Yang, or Blood. Therefore, the following categorized lists present additional symptoms that assist in narrowing down the area of weakness within the body.
Qi Deficiency
- Slight shortness of breath
- Slight sweating
- Tiredness
- Weak voice
- Lack of appetite
Yin Deficiency
- Feeling of heat in the evening
- Night sweating
- Low grade fever
- Dry throat at night
- Thin body
Yang Deficiency
- Frequent, pale urination
- Cold limbs
- Feeling cold
- Bright, pale face
- No thirst
- Desire for hot drinks
- Loose stools
Blood Deficiency
- Numbness and tingling
- Blurred vision
- Tiredness
- Dull, pale face
- Pale lips
- Dry hair
- Poor memory
- Insomnia
- Scanty periods
Pathology
The pathology of Excess/Deficiency conditions fall into six different categories. The chart below breaks down how Zheng Qi and Xie Qi interact with each other, and how they are used to determine whether a condition is Excess or Deficiency.
| Xie Qi (Pathogenic Factor) | Zheng Qi (Qi and Blood) | Type of Condition |
| No Pathogenic Factor | Normal | Healthy |
| No Pathogenic Factor | Deficient | Deficiency |
| Strong Pathogenic Factor | Strong | Excess |
| Strong Pathogenic Factor | Deficient | Excess/Deficiency |
| Weak Pathogenic Factor | Strong | Excess/Deficiency |
| Weak Pathogenic Factor | Deficient | Excess/Deficiency |
Healthy
This condition is rarely seen in clinical practice. This is where the Zheng Qi is at a normal level and there is not an internal or external pathogenic factor (Xie Qi) present in the body. This is considered a state of “perfect health” in Eastern medicine.
Deficiency
These conditions tend to be chronic in nature and develop over a period of time. An example of a Deficiency condition is fatigue that develops from overwork or irregular diet. The symptoms for Deficiency conditions tend to be mild in nature, such as dull, achy pain.
Excess
This type of condition can be either acute or chronic. The symptoms of an Excess condition are severe in nature, such as sharp, stabbing pain. Most excess conditions are acute such as the onset of a cold with fever, nasal congestion, and a stiff neck/upper back.
Excess/Deficiency
Although the three categories of excess and deficiency are all considered “mixed” conditions, each condition is slightly different. For example, when the pathogenic factor is strong and the Zheng Qi is deficient, symptoms such as nasal congestion, stiff neck, and fever may be milder and last for a longer period of time. The stiffness could be full body and the fever could be low grade, and the symptoms could last for a couple of weeks. The reason for the milder symptoms and the longer duration is that the body does not have enough strength or resources to fight off the invading pathogen. The key with this category is that the symptoms may be more subtle or milder than if the body had strong Zheng Qi.
The second category of Excess/Deficiency is one in which the pathogenic factor is weak and the Zheng Qi is strong. Using the same example as mentioned above with fever, nasal congestion, and stiff neck, the individual would experience very mild symptoms—possibly to the point of being able to continue normal day-to-day activities. The person may not present with some nasal congestion but has a low or moderate fever and no body aches. The key is that these symptoms are milder than the previous example.
In the case where the pathogenic factor is weak and the Zheng Qi is weak, the symptoms are the mildest. Continuing to use the example of cold symptoms (fever, nasal congestion, stiff neck), the individual will not have a fever, may have minor nasal congestion, and may or may not have very mild body aches. In some cases, these types of conditions can linger for long periods of time and may or may not get better. The key in determining this condition is that these symptoms are the mildest of all conditions in this category.
Applying Concepts To Treatment Plans
Acupuncturists and Eastern medical professionals are trained in deciphering the root cause of a pattern of disharmony, and therefore it is always important to rely on the expertise of your medical provider.
The concepts of Excess and Deficiency are a foundational philosophy in the Eight Principles. An accurate diagnosis of the type of pattern, Excess or Deficiency, is important in the development of an appropriate treatment plan.
Just as Interior and Exterior as well as Yin and Yang were considered duality pairs, Excess and Deficiency represent a third duality pair. While Excess and Deficiency are used to determine the nature of the condition, this pair must be used in conjunction with the other duality pairs of the Eight Principles and other evaluation tools.
About the Author
As a practitioner and healer in Washington, DC for more than a decade, I take a patient-centered approach to care through acupuncture, cupping, herbal medicines, and mind-body coaching, with a specialty in full-spectrum reproductive health care.
