Consumers, health care financing, external and internal competition are factors identified in the medical literature as prompting change within medicine. I test these factors to determine if they also prompt regular doctors to define themselves as 'holistic MDs' and align themselves with complementary and alternative medicine (CAM). State-level regression analyses on the number of MDs advertising in referral directories for CAM therapies find holistic practice a function of practice locale. The proportion of holistic MDs increases in states with an older population, where more patients survive despite serious disabilities, and where non-physician providers pose a competitive threat. Consumer demand, specialization and licensing do not significantly influence adoption of CAM treatments in these analyses. Health care financing has disparate effects. Indemnity insurance constrains holistic practice while HMO penetration enhances it. These results suggest that holistic practice may be an integral part of the regular profession's ongoing professionalization project.