Chiropractic, also known as chiropractic care, is a health discipline that seeks to prevent and treat health problems by using spinal adjustments in order to correct misalignments, or subluxations. The brain and nervous system control and coordinate all the body's functions in part through nerve branches that exit from the spinal cord between the vertebrae. Slight spinal misalignments are said to interfere with the function of the nerve as it exits the verterbral foramina. Chiropractors were the first to infer a causal relationship between nerve interference or compression at the spine and subsequent problems in more distant parts or organ systems regulated by the nerve.
You can learn more about the science and history of chiropractic care by clicking here (wikipedia.org).