Basic research suggests that acupuncture works by regulating the body's nervous system, and by promoting the release of pain-killing chemicals (endorphins) and immune cells. Another possibility is that acupuncture alters brain chemistry, affecting brain chemicals and hormones associated with the immune process and regulation of blood pressure, blood flow and body temperature. . . . . Evidence suggests that acupuncture may help cancer patients by relieving nausea and vomiting after surgery or chemotherapy treatment. Studies are looking at the role of acupuncture in stroke rehabilitation and asthma treatment.