The classical Chinese explanation of acupuncture is that channels of energy run in regular patterns through the body and over its surface. These energy channels are called meridians in acupuncture theory. They are like rivers flowing through the body to irrigate and nourish the tissues. An obstruction in the movement of these acupuncture energy rivers is like a dam that backs up the flow in one part of the body and restricts it in others.

The meridians can be influenced by needling the acupuncture points; the acupuncture needles unblock the obstructions at the dams and reestablish regular flow through the acupuncture meridians. Acupuncture treatments can therefore help the body's internal organs to correct imbalances in the digestion, absorption, and energy production activities, and in the circulation of their energy through the meridians. The modern scientific explanation is that needling the acupuncture points stimulates the nervous system to release chemicals in the muscles, spinal cord, and brain. These chemicals will either change the experience of pain, or they will trigger the release of other chemicals and hormones which influence the body's own internal regulating system. The improved energy and biochemical balance produced by acupuncture results in stimulating the body's natural healing abilities, and in promoting physical and emotional well-being.