(from Lat. acus, "needle" (noun), and pungere, "prick" (verb) or in Standard Mandarin, zhen jiu, is a therapeutic technique intended to restore health and well-being. Acupuncture is widely considered to be one of the oldest and most commonly used medical procedures in the world. In China, the practice of acupuncture can be traced as far back as the 1st millennium BC, and archeological evidence has been identified with the period of the Han dynasty (from 202 BC to 220 AD). The practice spread centuries ago into many parts of Asia; in modern times it is a component of traditional Chinese medicine (TCM), and forms of it are also described in the literature of traditional Korean medicine where it is called chimsul. It is also important in Kampo, the traditional medicine system of Japan.
From a traditional Chinese medical view, acupuncture treats the human body as a whole and involves several "systems of function" that are in many cases associated with (but not identified on a one-to-one basis with) physical organs. Disease is understood as a loss of the body's natural regulatory mechanisms among these systems of function. Treatment of disease is attempted by modifying the activity of one or more systems of function through the application of needles, pressure, or heat on sensitive parts of the body traditionally called "acupuncture points" in English, or "xue" in Chinese.
Traditional Chinese medical theory holds that acupuncture works by normalizing the balance of "vital energy" (see qi) throughout the body. Pain or illnesses are treated by attempting to remedy local or systemic accumulations or deficiencies of qi. Pain or disease is considered to indicate blockage or stagnation of the flow of qi, and 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 "deqi" ("obtaining 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. An acupuncturist will decide which points to treat by thoroughly questioning the patient and utilizing a variety of diagnostic skills.
While the traditional view of acupuncture utilizes the concept of qi to define the processes involved in acupuncture treatment, the nature of qi is highly controversial, and controversy in Chinese philosophy as to the nature of qi still exists. Because of this, perhaps the easiest way to envision how acupuncture works is by analogy.
Electrical circuits are something most people are familiar with. Consider a light switch and the light itself. Although a light switch is located on a wall, it is capable of controlling a light on the ceiling. It can do this because there are wires inside the wall running from the switch to the light. When the switch is off, there is no light; when the switch is flipped on, the light turns on. Similarly, one might consider the body as having the same types of switches all over to control the body's functions. These "switches" are called acupuncture points.
Some of these points function much like a light switch: they do only one thing. For instance, some points are very good at relieving pain. Using the right points in combination, pain can often be turned off like a switch.
Another type of acupuncture point may act more like a thermostat that controls the temperature in a house. A thermostat allows one to set a temperature that is the most comfortable to them, and a heater goes on and off to adjust the heat or cold. Similarly, certain acupuncture points adjust things like stress response, energy and insomnia.