Chiropractic (from Greek chiro- χειρο- "hand-" + praktikós πρακτικός "concerned with action") is a complementary and alternative medicine health care profession that focuses on diagnosis, treatment and prevention of mechanical disorders of the musculoskeletal system and their effects on the nervous system and general health. It emphasizes manual therapy including spinal manipulation and other joint and soft-tissue manipulation, and includes exercises and health and lifestyle counseling.[1] Traditionally, it assumes that a vertebral subluxation or spinal joint dysfunction can interfere with the body's function and its innate ability to heal itself.[2]

D. D. Palmer founded chiropractic in the 1890s and his son B.J. Palmer helped to expand it in the early 20th century.[3] It has two main groups: "straights", now the minority, emphasize vitalism, innate intelligence, spinal adjustments, and subluxation as the leading cause of all disease; "mixers" are more open to mainstream and alternative medical techniques such as exercise, massage, nutritional supplements, and acupuncture.[4] Chiropractic is well established in the U.S., Canada and Australia.[5]

For most of its existence chiropractic battled with mainstream medicine, and was sustained by the antiscience philosophy of the straights.[6] Vaccination remains controversial among chiropractors.[7] In recent decades chiropractic gained legitimacy and greater acceptance by physicians and health plans, enjoyed a strong political base and sustained demand for services, and became more integrated into mainstream medicine,[8] and evidence-based medicine has been used to review research studies and generate practice guidelines.[9] Opinions differ as to the efficacy of chiropractic treatment;[10] the efficacy and cost-effectiveness of maintenance chiropractic care are unknown.[11] Although spinal manipulation can have serious complications in rare cases,[12] chiropractic care is generally safe when employed skillfully and appropriately.[13]