Spinal manipulation as a treatment for musculoskeletal complaints has been practiced for centuries. In the last 50 years, the use of spinal manipulation has been equated with the practice of chiropractic, and, in part because of this, the use of spinal manipulation has been labeled an unorthodox treatment by the medical profession. Recent research favorable to the chiropractic treatment of patients with low-back pain along with the current emphasis on patient outcomes, has helped stimulate a re-appraisal of the role of spinal manipulation. In this article, reprinted from Annals of Internal Medicine, the authors review the scientific literature on the use, complications, and efficacy of spinal manipulation for low back pain. Techniques for spinal manipulation can be broadly categorized as one of two types: nonspecific long-lever manipulations and specific, short-lever, high-velocity spinal adjustments. Long-lever manipulations use the femur, shoulder, head, or pelvis to manipulate the spine in a nonspecific manner, whereas short-lever spinal adjustments use a specific contact point on a process of a vertebra to affect a specific vertebral joint. It is this second method that is most closely identified with chiropractic practice. This article examines the use of lumbar spine manipulation of all types to treat low-back pain, and concludes that spinal manipulation is of short-term benefit in some patients, particularly those with uncomplicated, acute low-back pain, but that data are insufficient concerning the efficacy of spinal manipulation for chronic low-back pain.