Complementary and alternative medicine services in the United States are an approximately $9 billion market each year, equal to 3 percent of national ambulatory health care expenditures. Unlike conventional allopathic health care, complementary and alternative medicine is primarily paid for out of pocket, although some services are covered by most health insurance. Examining trends in demand for complementary and alternative medicine services in the United States reported in the Medical Expenditure Panel Survey during 2002-08, we found that use of and spending on these services, previously on the rise, have largely plateaued. The higher proportion of out-of-pocket responsibility for payment for services may explain the lack of growth. Our findings suggest that any attempt to reduce national health care spending by eliminating coverage for complementary and alternative medicine would have little impact at best. Should some forms of complementary and alternative medicine-for example, chiropractic care for back pain-be proven more efficient than allopathic and specialty medicine, the inclusion of complementary and alternative medicine providers in new delivery systems such as accountable care organizations could help slow growth in national health care spending.