Doctors of chiropractic - who are licensed to practice in all 50 states, the District of Columbia, and in many nations around the world - undergo a rigorous education in the healing sciences, similar to that of medical doctors. In some areas, such as anatomy, physiology, and rehabilitation, they receive more intensive education than most medical doctors of physical therapists.
Meeker W, Haldeman H. Chiropractic: A Profession at the Crossroads of Mainstream and Alternative Medicine. Annals of Internal Medicine 2002, Vol 136, No 3.