The ancient Chinese believed that there is a universal life energy called Chi or Qi present in every living creature. 

This energy is said to circulate throughout the body along specific pathways that are called meridians. As long as this energy flows freely throughout the meridians, health is maintained. Once the flow of energy is blocked or constricted, the system is disrupted and pain and illness occur. 

Acupuncture works by stimulating certain points on the meridians to release and open up the flow of Chi energy.