he ancient Chinese believed that energy-forces called meridians ran through the body. Blockages along these meridians could lead to sickness and other ailments, including infertility. Chinese acupuncture practitioners treat these blockages by painlessly inserting slender needles at different points along the meridians.

Many studies in animals and humans have demonstrated that acupuncture can cause multiple biological responses. These responses can occur locally, i.e., at or close to the site of application, or at a distance, mediated mainly by sensory neurons to many structures within the central nervous system.