Introduction

As I had mentioned in my last post, the word “Qi” (氣) does not refer to a singular concept. It has many meanings depending on context. Let’s explore the medical meanings a bit more closely.

In the theoretical foundations of Traditional Chinese Medicine, Qi (氣) is regarded as the fundamental vital energy that underlies life, health, and disease. It is simultaneously substance and function, material and dynamic.

The Huangdi Neijing (《黃帝內經》), compiled between the Warring States and Han periods, states:

「人以天地之氣生，四時之法成.」
“Human beings are born through the Qi of Heaven and Earth and are completed through the laws of the Four Seasons.”¹

This passage emphasizes that Qi connects human life to the rhythms of the natural world. In modern TCM theory, Qi is categorized according to its origin, location, and function. Below are the principal types of Qi as described in classical literature and interpreted in modern scholarship.

Note: This article makes reference to the Huangdi Neijing. The Neijing has two parts, the Suwen and the Lingshu. Footnotes hence make reference to either fo the two parts instead of the Neijing as a whole.

1. Yuan Qi (Original Qi, 原氣)

Yuan Qi is the primal motive force of all physiological processes. It originates from congenital Essence (Jing) stored in the Kidneys, and courses throughout the body passing through the sanjiao. It represents the dynamic functional expression of Essence. Jing is the root substance, Yuan Qi is its mobilized power, circulating throughout the body and activating life processes.

Source: Congenital Essence (Jing) in the Kidneys

Functions:

• Acts as the motive force for all physiological activities
• Activates and supports the function of Zang-Fu organs
• Promotes transformation of Qi
• Warms and nourishes the body through its dynamic movement
• Serves as the constitutional foundation of vitality and resistance

Note:

The term “Yuan Qi” does not appear explicitly in the Neijing.

Its physiological meaning — a pre-heaven motive Qi rooted in the Kidney/Mingmen — is described in several key passages (Suwen 1, 8; Lingshu 47).

The term itself was formalized later, particularly in the Ming dynasty by Zhang Jiebin (張介賓), in his 1624 work, the Lei Jing (《類經》)

「原氣者，人之先天之氣也，出於命門，為一身之本。」
“Yuan Qi is the pre-heaven Qi of human beings. It emerges from the Gate of Life (Mingmen) and is the root of the entire body.”²

Clinical relevance:
Yuan Qi deficiency (原氣虛) reflects a weakening of the body’s motive force, not a direct depletion of Essence. It may present as low vitality, weak Zang-Fu organ function, reduced resistance to disease, cold limbs, weak voice, and fatigue.

Yuan Qi deficiency often occurs secondary to Essence deficiency — for example, in cases of aging, chronic illness, or congenital weakness. Whereas Jing deficiency concerns the root substance of life, Yuan Qi deficiency reflects insufficient functional activity derived from that substance.

Scholars interpret Yuan Qi as the constitutional reserve or “pre-heaven Qi” comparable to genetic endowment and basal vitality.³

2. Gu Qi (Grain or Food Qi, 穀氣)

Gu Qi arises from the transformation of food and drink by the Spleen and Stomach. It represents the first stage of postnatal Qi formation.

Source: Nutrients transformed by the Spleen and Stomach

Functions:

• Raw material for Zong Qi, Ying Qi, and Wei Qi
• Provides basic postnatal nourishment

Clinical relevance: Deficiency manifests as poor appetite, fatigue, and lack of strength.

「水穀入胃，散精於肝，輸津於脾，上注於肺，通調水道，下輸膀胱。」
“Grains and water enter the Stomach, their essence disperses to the Liver, fluids go to the Spleen, ascend to the Lung, regulate water passages, and descend to the Bladder.”⁴

This concept aligns with the nutritional basis of vitality, forming the bridge between food intake and functional energy.⁵

3. Qing Qi (Clear Qi, 清氣) or Kong Qi (Air, 空氣)

Qing Qi refers to the clear, pure, light aspect of atmospheric Qi inhaled through the Lung. It combines with Gu Qi in the chest to form Zong Qi.

Source: Clean air inhaled by the Lung

Functions:

• Provides Yang Qi essential for physiological activity
• Combines with Gu Qi to generate Zong Qi

Clinical relevance: Deficiency may cause dyspnea, fatigue, and a weak or soft voice.

「人吸清氣而生，呼濁氣而死。」
“Human beings live by inhaling clear Qi and die when exhaling turbid Qi.”⁶

In modern TCM discourse, Qing Qi is often mentioned alongside Kong Qi (空氣) — the modern term for “air.”
While both terms may be used interchangeably in clinical education, Qing Qi has a broader theoretical meaning: it represents the vital clear energy extracted from inhalation, not merely the physical air itself. Kong Qi, by contrast, is simply the modern physical concept of air.⁷

4. Zong Qi (Gathering Qi, 宗氣)

Zong Qi, stored in the chest (膻中, dan zhong), arises from the combination of Gu Qi and Qing Qi. It is associated with both respiration and circulation.

• Source: Gu Qi + Qing Qi
• Functions:
  • Supports the Lung in respiration
  • Assists the Heart in circulation of Blood
  • Influences speech, voice, and emotional expression
• Clinical relevance: Zong Qi deficiency manifests as weak or shallow breathing, soft voice, palpitations, or cold limbs.

「宗氣積於胸中，出於喉嚨，以行呼吸，貫心脈而行血氣。」
“Zong Qi accumulates in the chest, emerges through the throat to control respiration, and penetrates the Heart vessels to move Blood and Qi.”⁸

Maciocia (2015) notes that Zong Qi reflects the integration of environmental and nutritional energy, and is central to the regulation of the upper burner.⁹

5. Zheng Qi (Upright Qi, 正氣)

Zheng Qi is the totality of the body’s defense and adaptive capacity, encompassing Yuan Qi, Zong Qi, Ying Qi, and Wei Qi. It represents the body’s ability to resist disease.

• Source: Combination of congenital and acquired Qi
• Functions:
  • Protects against external pathogenic factors (Xie Qi)
  • Maintains internal homeostasis
  • Supports recovery and repair
• Clinical relevance: Weak Zheng Qi is associated with susceptibility to infection, chronic illness, or delayed healing.

「正氣存內，邪不可干。」
“When upright Qi is present within, no pathogenic influence can invade.”¹⁰

Modern TCM scholars often liken Zheng Qi to the immune system and adaptive regulatory mechanisms. An example of this is that it is said that if Zheng Qi is weak, then cancer arises. Western medicine can be used to attack the cancer, and TCM used to fortify Zheng Qi.

6. Ying Qi (Nutritive Qi, 營氣)

Ying Qi circulates within the blood vessels and closely parallels Blood (血). It nourishes tissues, organs, and the mind.

• Source: Transformation of Gu Qi
• Functions:
  • Nourishes Zang-Fu organs, muscles, tissues, and the Shen
  • Supports cognitive and mental activity
• Clinical relevance: Deficiency may result in insomnia, pale complexion, cognitive weakness, or fatigue.

營出中焦，注於脈，化而為血，以營筋骨，濡肌膚。」
“Nutritive Qi emerges from the Middle Jiao, enters the vessels, transforms into Blood, and nourishes sinews, bones, and flesh.”¹¹

Wiseman (1996) and Maciocia (2015) emphasize the close relationship between Ying Qi and Blood, noting that they “share the same source and flow together.” My personal interpretation is that Ying Qi is a conceptual representation of oxygen and nutrients in the bloodstream.

7. Wei Qi (Defensive Qi, 衛氣)

Wei Qi flows outside the vessels, between the skin and muscles. It is more vigorous and coarse than Ying Qi, protecting the body from external pathogens.

Source: Coarser part of Gu Qi

Functions:

• Defends against external pathogens
• Regulates opening and closing of pores
• Maintains body temperature

Clinical relevance: Deficiency presents as spontaneous sweating, frequent colds, or aversion to wind.

「衛者，水穀之悍氣也。」
“Defensive Qi is the fierce and active Qi derived from grain and water.”¹²

Wei Qi is often likened to the body’s surface defense system, loosely comparable to innate immune barriers (Maciocia 2015).

8. Jing Qi (Essence Qi, 精氣) and Shen Qi (Spirit Qi, 神氣)

Although not “functional Qi” per se, Jing (Essence), Qi, and Shen (Spirit) — the “Three Treasures” (三寶) — form the foundation of human vitality.

Jing Qi: Stored in the Kidney, fundamental to growth, reproduction, and vitality.

Shen Qi: Governs mental activity, consciousness, and emotional stability.

Clinical relevance: Jing deficiency leads to constitutional weakness; Shen disturbance manifests as insomnia, anxiety, or cognitive decline.

「得神者昌，失神者亡。」
“Those who have Shen flourish; those who lose it perish.”¹³

Maciocia emphasizes the interdependence of the Three Treasures, observing that “Jing is the root, Qi is the function, and Shen is the manifestation.”

9. Xie Qi (Pathogenic Qi, 邪氣)

Xie Qi denotes pathogenic influences, both external (the Six Excesses: Wind, Cold, Summer-Heat, Dampness, Dryness, Fire) and internal (emotional disturbances, irregular lifestyle, etc.).

Source: External environment and internal disharmony

Effect: Disrupts normal Qi flow and balance, overcomes Zheng Qi if strong or if Zheng Qi is weak

Clinical relevance: Disease occurs when Xie Qi overpowers Zheng Qi.

Conclusion

Qi is not merely a metaphysical concept but a functional framework describing the dynamic processes that sustain life in Chinese medical thought.

When Qi is abundant, harmonious, and flowing, health is maintained. When Qi is deficient, stagnant, rebellious, or attacked by Xie Qi, disease manifests.

「氣行則血行，氣滯則痛。」
“When Qi flows, Blood flows; when Qi stagnates, pain arises.” ¹⁴— Lingshu, Chapter 55.

Modern TCM scholarship continues to engage with this classical concept, integrating it with contemporary understandings of physiology, homeostasis, and integrative health. Recognizing the different kinds of Qi — Yuan, Gu, Qing, Zong, Ying, Wei, and Zheng — provides a framework for nuanced clinical differentiation and treatment.

References:

• Maciocia, G. The Foundations of Chinese Medicine (3rd ed.), pp. 54–56.
• Wiseman, N. & Ellis, A. Fundamentals of Chinese Medicine, Paradigm Publications.
• Unschuld, P. Huang Di Nei Jing Su Wen, UC Press.
• Zhang, Jiebin. Lei Jing (類經). 1624. Chinese Text Project, https://ctext.org/lei-jing
• Shanghai College of Traditional Chinese Medicine. Zhongyi Xue Gailun (中醫學概論).

1. Suwen (《素問》), Chapter 1 ↩︎
2. Lei Jing (《類經》), ↩︎
3. Maciocia 2015; Unschuld 2011 ↩︎
4. Lingshu (《靈樞》), Chapter 18. ↩︎
5. Wiseman & Ellis 1996 ↩︎
6. Traditonal Neijing Commentary ↩︎
7. Maciocia 2015; Wiseman and Ellis 1996 ↩︎
8. Suwen (《素問》) Chapter 46 ↩︎
9. Maciocia 2015 ↩︎
10. Suwen (《素問》), Chapter 33 ↩︎
11. Lingshu (《靈樞》), Chapter 18. ↩︎
12. ibid. ↩︎
13. Lingshu (《靈樞》), Chapter 8 ↩︎
14. Lingshu (《靈樞》), Chapter 55 ↩︎