U.S. Government agency Report. In 1994, the Agency for Health Care Policy and Research published Clinical Practice Guideline.
The guideline defined acute low-back pain, evaluated various treatments, and made recommendations concerning the efficacy of those treatments.
Manipulation is one of the most safe and effective treatments for most cases of acute low-back pain. Regarding the guideline, the following editorial comments appeared in the Annals of Internal Medicine: “The Agency for Health Care Policy and Research (AHCPR) recently made history when it concluded that …spinal manipulation hastens recovery from acute low back pain and recommended that this therapy be used in combination with or as an alternative to non steroidal anti-inflammatory drugs…
Perhaps most significantly, the guidelines state that… spinal manipulation offers both pain relief and functional improvement”.

References:
Micozzi, Mark. 1998. “Complementary Care: When is it appropriate? Who will provide it?” Annals of Internal Medicine 129: 65-66