The traditional explanation of how acupuncture works is that complex networks called meridians or channels transport Qi to every part of the body. These channels can be thought of as rivers or highways. There are twelve channels on each side of the body, as well as one channel on the front, and the back of the body. There are fourteen channels in all. Over centuries of observation, the channels have been mapped out, and hundreds of specific points where they are most accessible have been located.
The meridians carry Qi through the body to the head, feet, legs chest, hands, arms, and internal organs. Qi is the vital life energy force. It is present in all living things. It is necessary that it is balanced in the body, and that the flow is not impeded. If the Qi flows in the wrong direction, or is blocked, it may result in pain, illness, or compromised function. Acupuncture unblocks the flow of Qi and reestablishes harmony in the body. This results in the return to good health.
The modern scientific explanation is that acupuncture stimulates the body to release chemicals and hormones in the muscles, spinal cord, and brain that reduce inflammation or nourish the immune system which influences the body's own internal regulating system.