1. The Concept of the Six Excesses
The Six Excesses (Liù Yín), namely Wind (Fēng), Cold (Hán), Heat (Shǔ), Dampness (Shī), Dryness (Zào), and Fire (Huǒ), are referred to as “Six Qi” (Liù Qì) under normal circumstances. They represent six different climatic changes in nature, which are essential for the growth of all living things and are harmless to the human body. However, when climatic changes are abnormal, such as excessive or insufficient Six Qi, or when Qi appears out of season (for example, cold in spring when it should be warm, or heat in autumn when it should be cool), and when climatic changes occur too abruptly (such as extreme heat or cold), the Six Qi can become pathogenic factors that invade the body and cause disease, especially when the body’s righteous Qi (Zhèng Qì) is insufficient and resistance is lowered. In this context, the Six Qi are termed “Six Excesses” (Liù Yín). The term “Yín” implies both excess and infiltration; since the Six Excesses are considered improper Qi, they are also referred to as “Six Evils” (Liù Xié). They belong to a category of pathogenic factors that cause external diseases.
2. Characteristics of the Six Excesses
External Pathogenicity: The Six Excesses primarily invade the superficial layers of the body, often entering through the mouth and nose, hence they are also known as “External Pathogenic Six Excesses”. The diseases caused by them are collectively referred to as external diseases.
Seasonality: The diseases caused by the Six Excesses often exhibit significant seasonality. For instance, Wind diseases are more common in spring, Heat diseases in summer, Damp diseases in late summer, Dry diseases in autumn, and Cold diseases in winter. However, multiple pathogenic factors can also occur in a single season.
Regionality: The diseases caused by the Six Excesses are often closely related to the living environment. For example, the northwest plateau region is prone to Cold and Dry diseases, while the southeastern coastal areas are more susceptible to Damp and Warm diseases.
Environmental Factors: The occurrence of diseases due to the Six Excesses is 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.
Combination: The Six Excesses can invade the body individually, such as Cold directly affecting the internal organs causing diarrhea; they can also combine to invade the body simultaneously, leading to conditions like Wind-Heat colds, Cold-Damp affecting the spleen, or Wind-Cold-Damp bi syndrome.
Transformation: The Six Excesses not only influence each other but can also undergo pathological transformations under certain conditions. For example, Cold can become Heat due to stagnation, prolonged Damp-Heat can transform into Dryness harming Yin, and all Six Excesses can transform into Fire due to heat. The reasons for these transformations include individual differences in constitution and improper treatment.