I don't fully know the science behind it, but the network of nerves are broken in "meridiens" or areas of the body. By stimulating certain nerves your nervous system is improved. They also attach a device to several needles and send electronic pulse to stimulate the nerve. As a Western culture we have been conditioned to ingest chemicals to cure our ills. Chemicals affect the nervous system: pain relief (numb the nerves); so why not direct nerver stimulation. After all, doesn't it feel great to have a massage, or get your back stratched?