Acupuncture is a collection of procedures involving penetration of the skin with needles to stimulate certain points on the body. In its classical form it is a characteristic component of traditional Chinese medicine (TCM). It has been categorized as a complementary health approach. According to traditional Chinese medicine, stimulating specific acupuncture points corrects imbalances in the flow of qi through channels known as meridians. Scientific investigation has not found any histological or physiological correlates for traditional Chinese concepts such as qi, meridians, and acupuncture points, and some contemporary practitioners use acupuncture without following the traditional Chinese approach.
The general theory of acupuncture is based on the premise that bodily functions are regulated by an energy called qi which flows through the body; disruptions of this flow are believed to be responsible for disease. Acupuncture describes a family of procedures aiming to correct imbalances in the flow of qi by stimulation of anatomical locations on or under the skin (usually called acupuncture points or acupoints), by a variety of techniques. The most common mechanism of stimulation of acupuncture points employs penetration of the skin by thin metal needles, which are manipulated manually or by electrical stimulation.