Many Americans use one or more health promotion, illness prevention or healing practices that are considered as complementary and alternative medicine (CAM).1 In recognition of this, the United States Congress legislated in 1991 to establish the Office of Alternative Medicine to “investigate and evaluate promising unconventional medical practices”. In 1998, Congress expanded this mandate by enacting legislation that created the National Center for Complementary and Alternative Medicine (NCCAM), endowing it with the resources and authority to fund research, train researchers, and disseminate information to the public and healthcare professionals.

A number of factors contributed to the creation of NCCAM. First was the popularity of unproven medical practices, with users of one or more CAM modalities tending to be women, people with higher education, those with an interest in the role of the mind in health, or those with some chronic illness.2 Second was an increasing recognition of the importance of traditional healing practices among an ethnically diverse American population. Third, in 1994, the US Congress passed legislation that permitted wide access to dietary supplements without confirmation of their composition, safety or efficacy, and a concomitant loosening of legal restraints on alternative practices such as chiropractic medicine and acupuncture.

Given the diversity of CAM approaches and questions about their safety and efficacy, setting research priorities for NCCAM is a significant challenge. The US$117.7 million allocated to NCCAM in 2004, while generous by most standards, permits only a limited sampling of possible CAM approaches. To develop its approach, NCCAM sought input from diverse communities of stakeholders. The resulting first strategic plan stressed investment in basic and clinical research, training, dissemination of findings, and integration of safe and effective practices.3 NCCAM made a commitment to aspire to the same rigorous standards that characterise National Institutes of Health (NIH) research in general, while its research priorities would focus on the most promising scientific opportunities. As NCCAM celebrates its fifth anniversary, it is possible to list its not inconsiderable achievements to date (see Box 1), and to reflect on some of the lessons learned for current and future directions.

Lessons learned at NCCAM forecast a future with a greater emphasis on preclinical and early-phase clinical studies that are designed to elucidate mechanisms, identify optimal dosing and schedules, and select appropriate target populations and control conditions before launching clinical trials. Clinical studies at all levels are increasingly being conducted as collaborative efforts between funded investigators and NCCAM staff, who provide technical guidance, from sophisticated design and statistical consultation, to advice on recruitment and retention. Research on natural products is being conducted within a framework in which NCCAM either provides well-characterised and standardised clinical trial materials for investigators to use, or tests products being used by investigators to assure characterisation and standardisation. Finally, NCCAM is taking full advantage of new technologies, from genomics to brain imaging, and applying them to new areas, such as the capacity of the mind to affect health, in its multidisciplinary research.

While NCCAM first built a domestic scientific constituency, it seeks to engender and strengthen relationships with other countries that have both established research in conventional medicine, and a tradition that is rich in indigenous practices. We invite scientific leaders in these countries to join the global CAM research effort.