Chinese medicine is based on a pre-scientific paradigm of medicine that developed over several thousand years. Its theory holds the following explanation of acupuncture:

Health is a condition of balance of yin and yang within the body. Particularly important in acupuncture is the free flow of Qi, a difficult-to-translate concept that pervades Chinese philosophy and is commonly translated as "vital energy"). Qi is immaterial and hence yang; its yin, material counterpart is Blood (capitalized to distinguish it from physiological blood, and very roughly equivalent to it). Acupuncture treatment regulates the flow of Qi and Blood, tonifying where there is deficiency, draining where there is excess, and promoting free flow where there is stagnation. An axiom of the medical literature of acupuncture is "no pain, no blockage; no blockage, no pain."

Many patients claim to experience the sensations of stimulus known in Chinese as de qi ("obtaining the Qi" or "arrival of the Qi"). This kind of sensation was historically considered to be evidence of effectively locating the desired point. (There are some electronic devices now available which will make a noise when what they have been programmed to describe as the "correct" acupuncture point is pressed).

TCM treats the human body as a whole that involves several "systems of function" generally named after anatomical organs but not directly associated with them. The Chinese term for these systems is Zang Fu, where zang is translated as "viscera" or solid organs and fu is translated as "bowels" or hollow organs. In order to distinguish systems of function from physical organs, Zang Fu are capitalized in English, thus Lung, Heart, Kidney, etc. Disease is understood as a loss of balance of Yin, Yang, Qi and Blood (which bears some resemblance to homeostasis). Treatment of disease is attempted by modifying the activity of one or more systems of function through the activity of needles, pressure, heat, etc. on sensitive parts of the body of small volume traditionally called "acupuncture points" in English, or "xue" (穴, cavities) in Chinese. This is referred to in TCM as treating "patterns of disharmony."