Acupuncture analgesia has been used in treating pain as an alternative or complementary medicine.Selection of acupoints is very important in acupuncture treatment. Pain-relieving effects produced by stimulation ofhomotopic and heterotopic acupoints may be different and mediated by different mechanisms. Characteristics ofhomotopic and heterotopic acupuncture will be explained, focusing on pain inhibitory effects, and their underlyingmechanisms will be discussed.