The so-called Six Excesses (Liù Yín) refer to the six types of external pathogenic factors: Wind (Fēng), Cold (Hán), Heat (Shǔ), Dampness (Shī), Dryness (Zào), and Fire (Huǒ). The changes in Yin and Yang, the alternation of Cold and Heat, and the variations in climate all follow certain rules and limits. When climatic changes are abnormal, leading to excessive or insufficient Six Qi, or when these Qi appear out of season, or when climate changes occur too abruptly, surpassing a certain limit, the body may fail to adapt, resulting in the onset of disease. Thus, the Six Qi transform from being harmless to harmful, becoming pathogenic factors.
In general, the characteristics of diseases caused by the Six Excesses include the following aspects:
External Pathogenic
External Pathogenic: The Six Excesses primarily invade the superficial layers of the body or enter through the mouth and nose, hence they are also referred to as “External Pathogenic Six Excesses”. The diseases caused are collectively known as external diseases.
Seasonal
Seasonal: Diseases caused by the Six Excesses often have distinct seasonal characteristics. For example, Wind diseases are more common in spring, Heat diseases in summer, Damp diseases in late summer, Dryness diseases in autumn, and Cold diseases in winter. However, multiple pathogenic factors can occur in a single season.
Geographical
Geographical: The diseases caused by the Six Excesses are often closely related to the living environment. For instance, Cold and Dry diseases are more prevalent in the northwest plateau regions, while Damp and Warm diseases are more common in the southeastern coastal areas.
Coexisting
Coexisting: The Six Excesses can invade the body individually, such as Cold directly affecting the internal organs causing diarrhea; they can also combine in various ways to cause disease, such as Wind-Heat colds, Cold-Dampness obstructing the Spleen, and Wind-Cold-Dampness bi syndrome.
Transformative
Transformative: Although each of the Six Excesses has its own characteristics, they are not isolated; they can influence each other and under certain conditions, their pathological nature can transform. For example, Cold can become Heat due to stagnation, prolonged Heat-Dampness can transform into Dryness harming Yin, and all Six Excesses can transform into Fire due to Heat. The reasons for transformation include individual constitution differences and improper treatment.
Environmental
Environmental: The diseases caused by the Six Excesses are also closely related to the surrounding environment. For instance, prolonged exposure to damp environments can lead to Dampness-related diseases, while those working in high temperatures often experience Dryness or Fire-related diseases.
The specific characteristics of each excess are as follows:
1. Wind Evil (Fēng Yī)
(1) Wind is a Yang evil, characterized by its ability to disperse and invade Yang positions.
“Those harmed by Wind are first affected above.”
(2) Wind moves quickly and changes frequently.
(3) Wind is proactive.
“When Wind prevails, movement occurs.”
(4) Wind is the leader of all diseases.
“Among the Six Qi, only Wind can combine with all five Qi. If combined with Cold, it is called Wind-Cold; with Heat, it is called Heat-Wind; with Dampness, it is called Wind-Damp; with Dryness, it is called Wind-Dry; with Fire, it is called Wind-Fire. This is because Wind can stir these five Qi and harm people, hence it is called the leader of all diseases. The other five Qi cannot fully combine with each other; for instance, Cold cannot combine with Heat or Fire, Heat cannot combine with Cold, Dampness cannot combine with Dryness, Dryness cannot combine with Dampness, and Fire cannot combine with Cold. From this, it can be seen that many diseases arise from Wind.”
2. Cold Evil (Hán Yī)
(1) Cold is a Yin evil, which easily harms Yang Qi.
“When Yin prevails, Yang becomes ill.”
(2) Cold causes stagnation and is associated with pain.
“When Cold enters the meridians, it causes stagnation, leading to pain; if it resides outside the pulse, it results in blood deficiency; if it resides within the pulse, it causes Qi obstruction, hence sudden pain occurs.”
(3) Cold causes contraction.
“Cold causes Qi to contract.”
3. Heat Evil (Shǔ Yī)
(1) Heat is a Yang evil, characterized by its fiery nature.
(2) Heat rises and scatters, disturbing the spirit and depleting fluids and Qi.
“When it is intense, the pores open, the nutritive and defensive Qi communicate, and excessive sweating occurs, leading to Qi depletion.”
(3) Heat often carries Dampness.
4. Damp Evil (Shī Yī)
(1) Dampness is a Yin evil, which easily obstructs Qi mechanisms and harms Yang Qi.
It easily injures Spleen Yang; “When Dampness prevails, it leads to diarrhea; if severe, it can cause water retention and swelling.”
(2) Dampness is heavy and turbid.
(3) Dampness is sticky and diffusive.
(4) Dampness tends to descend and easily invades Yin positions.
“Yang is affected by Wind evil, while Yin is affected by Dampness; those harmed by Wind are first affected above, while those harmed by Dampness are first affected below.”
5. Dry Evil (Zào Yī)
(1) Dryness is characterized by its dryness and easily harms body fluids.
“When Dryness prevails, it causes dryness; all dryness leads to desiccation, cracking, and peeling, which are all attributed to Dryness.”
(2) Dryness easily harms the Lungs.
6. Fire Evil (Huǒ Yī)
(1) Fire is a Yang evil, characterized by its upward nature.
(2) Fire easily disturbs the spirit.
(3) Fire easily depletes fluids and Qi.
“Intense Fire consumes Qi.”
(4) Fire easily generates Wind and stirs blood.
“Extreme Heat generates Wind.”
(5) Fire easily causes swelling and ulcers.
“Abscesses and sores originate from Fire toxicity.”
In Traditional Chinese Medicine, in addition to identifying the Six Excesses as causes of disease, the characteristics of the Six Qi are also linked to the symptoms of the disease, forming disease names such as Wind Syndrome (Fēng Zhèng), Cold Syndrome (Hán Zhèng), Damp Syndrome (Shī Zhèng), Fire Syndrome (Huǒ Zhèng), Dry Syndrome (Zào Zhèng), etc. These syndromes have a certain causal relationship with the Six Excesses.
For example, Wind evil invasion can lead to external Wind-Cold, but some conditions may not be classified as external diseases yet exhibit similar symptoms to Wind, Cold, Dampness, and Fire, such as Wind rash, which typically presents with rapid onset, quick resolution, and itching, resembling the characteristic of Wind’s “ability to move and change frequently”. It is generally believed to be caused by Wind evil, but due to the dysfunction of Yin, Yang, Qi, and Blood in the organs, certain similar properties and symptom characteristics to the external Six Excesses can also arise.
In TCM, to differentiate from external Six Excesses, they are referred to as internal Wind, internal Cold, internal Dryness, internal Fire, and internal Dampness. The following discussion will focus on the external Six Excesses, including the characteristics of pathogenic factors and the related symptoms.
