Low back pain is a common problem. Traditional treatments that are helpful for some patients with low back pain include drugs (pain killers, anti-inflammatory drugs, and muscle relaxants), physical therapy, and back exercises. Treatments that are not helpful include traction, bed rest, corsets, topical gels, heat therapy, and certain types of massage. Spinal manipulation is an alternative treatment for low back pain. For spinal manipulation, a specially trained person (chiropractor, physician, or physical therapist) uses his or her hands to move the bones in the spine. Experts disagree about the role of spinal manipulation in treating low back pain. Spinal manipulation may be more likely to help certain types of patients with back pain than others. A previous study developed a rule based on 5 characteristics of patients with low back pain who achieved benefit from spinal manipulation. In that study, patients who met at least 4 of the 5 characteristics were most likely to benefit from spinal manipulation. However, this rule has not been tested in other patients.