Acupuncture is an ancient Chinese treatment using thin needles inserted at specific points in the body. It is based on the belief that energy (qi) flows through meridians and illness occurs when qi is blocked. The needles may alleviate pain by stimulating the nervous system to release chemicals or affect brain chemistry. Current evidence supports acupuncture for back/neck pain, headaches, and nausea. Risks are generally minor but may include bruising or fainting. Serious risks like infection or organ puncture are very rare if done properly. The document provides details on the theory, mechanisms of action, appropriate conditions, procedures, risks and side effects of acupuncture.