Qi

Qi in pre-Qin philosophy

In pre-Qin texts, qi (氣) is a term with several uses rather than one settled doctrine. The Stanford Encyclopedia of Philosophy article on Mencius, by Bryan Van Norden, says that Zhuangzi's writings present qi as an impersonal fluid that flows through all things and binds them together. It quotes a Zhuangzi passage in which the figure of Confucius advises listening with qi rather than with the heart. The same article presents Mencius's line, 'What you do not get from your heart, do not seek for in the qi,' as a deliberate reversal of that Zhuangzi emphasis. It does not discuss the passage in Mencius 2A2 on a 'flood-like' qi.

The Stanford Encyclopedia of Philosophy article on Xunzi, by Paul R. Goldin, says that Xunzi rarely used the term and did not build it into his metaphysics. Qi becomes important in the Han period, when Lu Jia added it to a theory in which a government's misconduct produces disasters and omens. The article presents this use as an innovation beyond Xunzi. The sources reviewed for this page give no dated account of qi in the primary texts of Mencius, Zhuangzi or Xunzi beyond these encyclopedia summaries, and the primary texts were not checked directly.

Qi in classical and later Chinese medicine

The Huangdi Neijing (Yellow Emperor's Inner Canon) is the foundational text of Chinese medical theory, dated by a Yo San University summary of the text to the fourth to second centuries BCE, and it is divided into the Suwen (Basic Questions), which covers theory, natural philosophy and diagnosis, and the Lingshu (Spiritual Pivot), which covers practical application and acupuncture. The summary is written by a teaching institution that offers training in the subject, and it reports scholarly agreement on dating without citing the evidence for it.

The Medical Subject Headings record for Qi, maintained by the US National Library of Medicine, gives the scope note 'the vital life force in the body, supposedly able to be regulated by acupuncture'. The record says the term roughly corresponds to the Greek pneuma, the Latin spiritus and the Indian prana. A 2009 editorial in Evidence-Based Complementary and Alternative Medicine describes the 2007 WHO Western Pacific standard terminology for traditional medicine, which lists qi-related headings such as Essential Qi theory and Qi-blood pattern identification. The editorial does not define qi itself.

Reading the qi passages

Reading of the qi passages themselves is limited to two abstracts. A 2025 study in the Journal of Beijing University of Traditional Chinese Medicine examines defensive qi in the text and reports that the Neijing describes its circulation and distribution in ways that overlap with other forms of qi and with yang, so that later physicians inherited a somewhat unsystematic account. A companion abstract by Koh and Cochrane in the Australian Journal of Acupuncture and Chinese Medicine describes the text as layered, the work of several contributors, with a channel theory that is complex and dynamic. The full passages were not read for this page.

The term and its translations

Qi is written 气 in simplified Chinese and 氣 in traditional characters. Romanizations include ch'i, the form used in the MeSH entry terms, and chi, a common English spelling. In English-language health writing it is often rendered as life force, vital energy or energy. A 2024 paper in Medical Acupuncture by Clare Foley and Gerhard Litscher argues that qi is questionably translated in the West as the biblical idea of lifeforce, and that its meaning may be closer to the Western scientific definition of energy as the material basis of everything in the universe. The authors state that their aim is to improve patient-practitioner communication. Their reading is one interpretation among several.

Related terms and points of difference

Qi is discussed alongside related concepts in Chinese medical writing. The Eigenschink review describes qi as the vital force believed to circulate through the body via meridians, so the two are discussed together in that framework. The WHO-regional terminology places qi within a basic-theory category with yin-yang theory and five-phase theory, and separately with essence, spirit, blood, fluid and humor. The main point of difference in the sources is whether qi should be read as the physical energy of physics. The Foley and Litscher paper argues that the closer reading is physical, while the Eigenschink review treats qi as a philosophical theory without a scientifically established basis.

Where the concept appears

Qi is a central term in Traditional Chinese Medicine, where its patterns and circulation are used in describing diagnosis and treatment. The Eigenschink review states that TCM's core premises, including qi, underpin its theories. The WHO-regional terminology includes diagnostic categories such as Qi-blood pattern identification. Qi also appears in acupuncture, where the NCCIH acupuncture page notes that the practice originated from traditional Chinese medicine, and in qigong and tai chi teaching, where qi is described as cultivated or moved. This page does not describe any procedure.

What adherents say it implies

Practitioners and reference descriptions treat qi as a vital life force and as something that moves through the body and affects health when it is balanced or disturbed. These are beliefs held within the traditions, and they are described here as attributed claims rather than tested findings. The sources reviewed do not describe a single agreed doctrine. The Mencius and Xunzi encyclopedia entries show qi used in different ways in pre-Qin texts, and TCM uses it in clinical pattern language. Readers who want practice-level detail should see the Acupuncture, Qigong, Tai chi and Traditional Chinese Medicine pages on this site.

Explanations offered within traditional medicine

Within traditional Chinese medicine, qi is described as the basis of physiological function and the movement of blood and fluids, and as a way of explaining disease patterns and treatment effects. The Eigenschink review reports that qi is said to flow through the meridian system, and that the meridians are used to explain the effects of acupuncture. The review judges the studies used to validate the meridians to be methodologically weak and inconsistent, and it treats these explanations as claims within the traditional framework.

The NCCIH acupuncture page says that how acupuncture works is not fully understood. It lists possible effects on the nervous system, direct effects on connective tissue, and nonspecific effects that include the patient's belief in the treatment and the relationship with the practitioner. The page does not attribute these effects to qi.

Claims made for qigong and tai chi

Qigong and tai chi are described as improving mood, sleep, balance and fatigue. A 2024 BMJ network meta-analysis of exercise for depression reported that tai chi or qigong had a moderate pooled effect on depression compared with active controls (Hedges' g -0.42, 95% credible interval -0.65 to -0.21). The authors rated confidence in the network results as very low for tai chi or qigong, and they found that only one study met the Cochrane criteria for low risk of bias across the exercise trials. The result concerns a measured outcome. It does not address whether qi exists.

Attempts to measure qi

The Eigenschink review reports no direct measurement of qi. It reviews attempts to validate the meridians through which qi is said to flow, including radiotracer studies, skin impedance measurements and anatomical dissection, and judges them methodologically weak and inconsistent. It concludes that the authors could not determine a scientifically justified basis for the existence of qi and the meridians. The review's conclusion is limited to the evidence it assessed.

Qigong literature includes reports of external qi, a term for qi said to be emitted by practitioners. This page did not verify those reports and does not rely on them. The NCCIH acupuncture page separately states that research on how acupuncture works remains incomplete, which is a different question from whether qi can be measured.

Measured outcomes in acupuncture research

Vickers and colleagues pooled individual patient data from 29 randomized trials, including 17,922 patients, on acupuncture for chronic back and neck pain, osteoarthritis, chronic headache and shoulder pain. They reported that acupuncture was superior to both sham and no-acupuncture controls for each condition. The authors also reported that the differences between true and sham acupuncture were relatively modest, and they suggested that factors beyond the specific effects of needling contribute. The outcomes in these trials are pain scores, and they do not include any measure of qi.

The NCCIH acupuncture page notes that in many studies the benefit of acupuncture has been greater against no treatment than against sham procedures, which the page reads as evidence that nonspecific effects contribute to the benefit. The page does not establish a specific mechanism that involves qi.

Critical reviews and the explanatory gap

Critical reviews name the gap between qi as a concept and measurable physiology. The Eigenschink review concludes that the core premises of TCM, including qi and meridians, lack a scientifically viable basis, and it reports that pulse and tongue diagnosis showed low inter-rater and intra-rater reliability. The Foley and Litscher paper takes a different line. It argues that qi may be read as a physical concept of energy, which would make the question one for physics rather than physiology. The two positions disagree about whether qi is a scientific claim at all, and neither reports a measurement that settles the question.

Within qigong research, the trials and reviews are mostly small or of low certainty. The BMJ network meta-analysis reported very low confidence for most treatments in its comparison, and it found that results were robust to publication bias while noting the limited quality of individual studies. The Eigenschink review reports no direct measurement of qi, and this page found no source that reports one. The research reviewed here examines outcomes such as pain, mood and balance, not qi itself.

Harms reported for acupuncture

The NCCIH acupuncture page states that when acupuncture is not delivered properly it can cause serious adverse effects, including infections, punctured organs and injury to the central nervous system. A 2017 overview of systematic reviews on acupuncture adverse events, by Chan and colleagues in Scientific Reports, identified four categories of adverse events: organ or tissue injuries, infections, local reactions, and other complications such as dizziness or syncope. The overview describes serious adverse events as rare but notes that they can be associated with death, and it rates the methodological quality of the included reviews as mediocre.

None of the sources reviewed for this page reports harm from the concept of qi itself. The harms above belong to the acupuncture and related practices that use qi language, and they are not evaluated here. The Eigenschink review also describes the evidence for TCM herbal remedies as poor and cites contamination and substitution problems, which are product-quality concerns for those remedies.

Care boundaries

A qi-based account of symptoms is not a substitute for diagnosis or for necessary medical care. The Eigenschink review concludes that the evidence for TCM diagnosis is limited, and the BMJ and Vickers studies report modest or low-certainty benefits for pain, mood and related outcomes. These findings do not support using qi-based practices in place of conventional care. Anyone with a serious or persistent symptom should seek assessment from a qualified clinician.