The so-called Six Excesses (Liuxie) refer to the six types of external pathogenic factors: Wind (Feng), Cold (Han), Heat (Shu), Dampness (Shi), Dryness (Zao), and Fire (Huo). The changes in Yin and Yang, the alternation of cold and heat, and climatic variations all follow certain rules and limits. When climatic changes are abnormal, and the Six Qi are excessive or insufficient, or occur at inappropriate times, or when climatic changes are too abrupt, exceeding certain limits, the body may fail to adapt, leading to the onset of disease. Thus, the Six Qi transform from being harmless to harmful, becoming pathogenic factors.
Under normal circumstances, Wind, Cold, Heat, Dampness, Dryness, and Fire are the six types of climatic changes in nature, referred to as “Six Qi”. The normal operation and variation of the Six Qi are beneficial for the growth and change of all things. However, if the Six Qi are excessive or insufficient, it leads to abnormal climate, which can become pathogenic when the body’s resistance is low, thus termed “Six Excesses” or “Six Evils”.
The Six Excesses are primarily introduced from the outside and are often related to seasonal climate and living environment. For example, spring is prone to Wind diseases, winter to Cold diseases, autumn to Dryness diseases, and summer or high-temperature work can lead to Heatstroke, while living in damp conditions can easily lead to Dampness evils.
The Six Excesses can act independently to cause disease, or two or three types of evils can simultaneously invade the body, such as Wind-Cold flu, Wind-Heat flu, Damp-Heat jaundice, and Wind-Cold-Damp Bi syndrome, and they can transform into one another, such as Wind-Cold transforming into internal Heat; unresolved Heat can consume body fluids and transform into Dryness; extreme Heat can generate Wind, etc.
In TCM, in addition to identifying the Six Excesses as pathogenic causes, the characteristics of the Six Qi are also linked to the symptoms of the disease, forming disease names such as Wind syndrome, Cold syndrome, Damp syndrome, Fire syndrome, Dryness syndrome… These syndromes have a certain causal relationship with the Six Excesses. For instance, invasion by Wind evil can lead to external Wind-Cold, but some conditions do not require external diseases yet present similar symptoms to Wind, Cold, Dampness, Dryness, and Fire, such as Wind rash, which typically presents with sudden onset, rapid 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. Due to the dysfunction of Yin-Yang, Qi, and Blood in the organs, similar properties and symptoms to the external Six Excesses can also arise, which TCM refers to as internal Wind, internal Cold, internal Dryness, internal Fire, internal Dampness, commonly known as “Five Internal Evils”. The following discussion focuses on the external Six Excesses, including the characteristics of pathogenic factors and related symptoms.
The Six Excesses: a term in pathology referring to the collective name for the six pathogenic evils: Wind, Cold, Heat, Dampness, Dryness, and Fire. When the Six Qi are excessive, insufficient, or inappropriate, they affect the body’s regulatory and adaptive functions and the propagation of pathogens, becoming pathogenic evils, classified as external diseases (including some epidemic and infectious diseases). The Six Excesses cause disease from the outside, referred to as external causes. “San Yin Ji Yi Bing Zheng Fang Lun”: “The Six Excesses are the constant Qi of heaven; if they invade, they first flow into the meridians and internally associate with the organs, being caused by external factors.”
1. Common Characteristics of the Six Excesses Causing Disease
1. External pathogenicity: This refers to the invasion of the body by pathogens from the skin surface or through the mouth and nose; it also refers to the initial stage of experiencing the Six Excesses.
2. Seasonality: Diseases caused by the Six Excesses often have significant seasonality, such as more Heat diseases in summer.
3. Regionality: Diseases caused by the Six Excesses are often closely related to the living area and environment, such as the cold and dry climate in the northwest plateau.
4. Coexistence: The Six Excesses can invade the body independently or simultaneously.
5. Transformability: Under certain conditions, the nature of the symptoms caused by the Six Excesses can transform. For example, an exterior Cold syndrome can transform into internal Heat syndrome.
The reasons for transformation include two points: one is the different constitution of individuals; the other is improper treatment.
2. The Nature and Pathogenic Characteristics of Each of the Six Excesses
(1) Wind Evil
1. Basic Concept: The external evil characterized by lightness, mobility, and non-stationary nature in the natural world is called “Wind Evil”. Wind Evil causes external Wind diseases. Wind Evil can occur in all four seasons, but spring is particularly susceptible to Wind Evil. Ancient poetry states, “The spring wind in February is like scissors,” and the saying, “The spring wind breaks the glazed tiles,” indicates that Wind Evil is particularly rampant in spring, making early prevention beneficial for health. TCM advises “to keep warm in spring and cool in autumn” to prevent Wind Evil from invading the body and causing Wind diseases.
So, where should we keep warm in spring?
Head — the head is where all Yang converges, and Yang Qi gathers here. TCM states that the upper body is Yang, while the lower body is Yin. For special groups such as the elderly and children, or those with weaker bodies, wearing a hat is necessary.
Feet and Legs — Cold arises from below, and the lower body is Yin, making it easily invaded by Yin Cold, so the feet and legs should be kept warm. The Back — our back has a governing vessel (Du Mai) that runs along it, so keeping the back warm can secure Yang Qi.
Neck — the neck has the Dazhui point and Fengfu point; if not well protected, symptoms of shoulder and neck pain may occur.
Abdomen — for women, it is essential to protect the abdomen, as it contains many critical acupoints. Poor protection can lead to Cold in the uterus, which can cause dysmenorrhea, irregular menstruation, or difficulty in conception.
2. Nature and Pathogenic Characteristics of Wind Evil:
(1) Wind is light and dispersive, easily attacking Yang positions:Wind is a Yang evil, characterized by lightness, upward movement, outward dispersal, and elevation. When Wind Evil invades the body, it can cause the body’s pores to open and sweat to flow, manifesting as symptoms of sweating and aversion to wind. Wind Evil often invades the upper body, skin surface, and Yang positions of the waist and back; thus, strokes can lead to cerebrovascular diseases, and common symptoms of colds include headaches, nasal congestion, and throat itching or pain.
(2) Wind is active and changes frequently:Active refers to the nature of Wind in the natural world, which moves and flows, indicating that Wind Evil’s invasion of the body has the characteristic of migrating and being unpredictable. For example, “moving Bi” caused by excessive Wind can lead to joint pain in the limbs that is migratory and variable. Frequent changes refer to the rapid onset and change of symptoms caused by Wind Evil. For instance, urticaria caused by Wind Evil can lead to skin itching, with a sudden onset that can spread throughout the body in minutes, disappearing without a trace, hence the saying that it appears and disappears unpredictably.
(3) Wind is proactive:Wind in nature has the characteristic of being active and non-stationary. When Wind Evil invades the body, it can cause symptoms of shaking and trembling. For example, in clinical practice, if a person suffers an injury and is then invaded by Wind Evil, symptoms such as limb convulsions and opisthotonos may occur.
(4) Wind is the leader of all diseases:Wind, as the leader, has two meanings. First, it refers to Wind as the precursor of external pathogenic factors; the other five evils often attach to Wind to invade the body, so ancient people regarded Wind Evil as the general term for external pathogenic factors.
Second, it indicates that Wind Evil is widely pathogenic, easily invading the body and causing various diseases. Wind Evil often combines with other evils to invade the body, combining with Heat to form Wind-Heat; with Cold to form Wind-Cold; with Dampness to form Wind-Damp; and with Phlegm to form Wind-Phlegm.
(2) Cold Evil
1. Basic Concept: The external evil characterized by coldness and stagnation is called “Cold Evil”. Cold Evil leads to external Cold diseases. Cold Evil is most commonly seen in winter. Cold Evil can be classified into two types: Cold damage to the skin surface, known as “Shang Han”; and Cold penetrating internally, damaging the Yang Qi of the organs, known as “Zhong Han”.
2. Nature and Pathogenic Characteristics of Cold Evil
(1) Cold is a Yin evil, easily damaging Yang Qi:Cold Evil is characterized as Yin, with a clear and cold nature. When Cold Evil invades the body, it leads to an excess of Yin Cold, which most easily damages the body’s Yang Qi.
(2) Cold is stagnant and causes pain:Stagnation refers to blockage. Cold Evil invading the body can slow down the movement of Qi, Blood, and body fluids, causing them to congeal and obstruct. Since Blood and body fluids “move when warm and congeal when cold,” and “blockage leads to pain,” Cold Evil can cause various pain symptoms in the body. The characteristic of pain caused by Cold Evil is that it worsens with cold and alleviates with warmth.
(3) Cold causes contraction:Cold Evil invading the body can cause the Qi mechanism to contract, leading to closed pores and constricted meridians and tendons.
3. Clinical manifestations:
One is that Cold Evil invades the skin surface, leading to closed pores, fever, aversion to cold, and absence of sweating.
The other is that Cold Evil invades the meridians, causing contraction and pain in the joints, with difficulty in flexion and extension.
(3) Damp Evil
1. Basic Concept: The external evil characterized by heaviness, turbidity, stickiness, and downward tendency is called “Damp Evil”. Damp Evil leads to external Damp diseases. External Damp diseases are most commonly seen in the long summer season, which is the time of year when humidity is at its peak.
2. Nature and Pathogenic Characteristics of Damp Evil
(1) Damp is a Yin evil, easily obstructing Qi and damaging Yang Qi:Dampness is a tangible evil that can invade the body and easily stagnate in the organs and meridians, obstructing the movement of Qi.
(2) Damp is heavy and turbid:“Heavy” refers to the feeling of heaviness and oppression. Damp Evil invading the body can lead to symptoms of heaviness and oppression. “Turbid” refers to the nature of secretions and excretions being unclear and foul.
(3) Damp is sticky:Damp Evil has a sticky and stagnant nature, which manifests in two aspects: one is the stickiness of symptoms, such as Damp stagnation in the large intestine leading to sticky and unsatisfactory stools; the other is the chronic nature of the disease. Due to the sticky nature of Dampness, it can linger in certain organs and tissues, making it difficult to resolve, hence Damp Evil often leads to prolonged and recurrent illnesses.
(4) Damp tends downward, easily invading Yin positions:Dampness, like water, tends to go downward, making Damp Evil easily invade the lower parts of the body.
(4) Dry Evil
1. Basic Concept: The external evil characterized by dryness, contraction, and cleansing is called “Dry Evil”. Dry Evil invades the body, leading to a series of dry symptoms, resulting in Dry diseases. Dry Evil is most commonly seen in autumn, with distinctions between cool dryness and warm dryness. In early autumn, the residual heat of summer combines with the dryness of autumn to form “warm dryness”; in late autumn, the cold air of early winter combines with the dryness of autumn to form “cool dryness”.
2. Nature and Pathogenic Characteristics of Dry Evil
(1) Dryness is characterized by aridity, easily damaging body fluids:Dryness represents a lack of body fluids. When Dry Evil invades the body, it most easily damages the body’s Yin fluids, leading to various dry and obstructive symptoms in the skin and orifices.
(2) Dryness easily harms the lungs:The lungs are delicate organs that prefer moisture and dislike dryness. The lungs govern Qi and respiration and are directly connected to the external atmosphere. The lungs also open to the nose and connect with the skin. Therefore, when Dry Evil invades, it most easily damages lung fluids, affecting the lungs’ physiological functions of dispersing and descending, leading to symptoms such as dry cough with little phlegm, or phlegm that is sticky and difficult to expel, or blood-streaked phlegm, as well as wheezing and chest pain. The lungs and large intestine are interrelated, so Dry Evil affecting the lungs can also lead to dry and difficult bowel movements.
(5) Fire (Heat) Evil
1. Basic Concept:The external evil characterized by the heat of fire is called “Heat Evil”. Heat Evil leads to external Heat diseases. Heat Evil is most commonly seen in summer.
2. Nature and Pathogenic Characteristics of Fire (Heat) Evil
(1) Fire heat is a Yang evil, easily damaging body fluids and consuming Qi:Heat is a Yang evil, and when Heat Evil invades the body, it can lead to high fever and a series of Yang heat symptoms. Heat Evil most easily forces body fluids to leak out, damaging the body’s Yin fluids; since body fluids carry Qi, when Heat Evil forces body fluids to leak, it often leads to Qi deficiency symptoms such as fatigue and weakness.
2. Fire heat rises:Heat Evil has an upward burning characteristic, so when it invades the body, it often presents with prominent upper body symptoms.
3. Heat Evil easily generates Wind and stirs Blood:“Generating Wind” refers to Heat Evil easily causing “Liver Wind to move internally,” which is also known as “extreme Heat generating Wind.” The mechanism for generating Wind has two points: one is that Heat Evil consumes body fluids, leading to malnourishment of the tendons and causing tremors; the other is that excessive Heat can promote Yang, causing Liver Yang to rise uncontrollably, which can transform into Wind.
“Stirring Blood” refers to Heat Evil easily causing various bleeding disorders, such as hemoptysis, hematochezia, and skin purpura. The mechanisms also include two points: one is that Heat Evil accelerates blood flow, forcing blood to overflow; the other is that Heat Evil can scorch blood vessels, causing bleeding.
4. Heat Evil easily disturbs the mind:Heat Evil invading the Ying and Blood levels can disturb the mind, leading to symptoms such as irritability, confusion, and delirium.
5. Fire Evil easily causes sores and abscesses:Fire Evil invading the blood level can accumulate in local areas, eroding flesh and leading to painful swellings and sores.
(6) Summer Heat Evil
1. Basic Concept: Summer Heat refers to the fire heat evil of summer, occurring between the summer solstice and the beginning of autumn, known as “Summer Heat Evil”. Summer Heat Evil has two significant characteristics: one is its obvious seasonality; the other is that Summer Heat Evil only arises from external sources, not from internal generation.
2. Nature and Pathogenic Characteristics of Summer Heat Evil
(1) Summer Heat is a Yang evil, characterized by heat:Summer Heat is the transformation of the fire heat of summer, thus it is a Yang evil. The heat of fire has the characteristic of being hot.
(2) Summer Heat rises and disperses, easily damaging body fluids and consuming Qi:Summer Heat, as a Yang evil, primarily rises and disperses, invading the body can cause the body’s pores to open and sweat to flow, damaging the body’s Yin fluids.
(3) Summer Heat often carries Dampness:Summer is not only hot but also a rainy season, increasing humidity in the air, so Summer Heat often invades the body along with Dampness.
