The use of complementary and alternative medicine (CAM) has grown dramatically in recent years, as has research on the safety and efficacy of CAM treatments. Minimal attention, however, has been devoted to the ethical issues relating to research on CAM. We argue that public health and safety demand rigorous research evaluating CAM therapies, research on CAM should adhere to the same ethical requirements for all clinical research, and randomized, placebo-controlled clinical trials should be used for assessing the efficacy of CAM treatments whenever feasible and ethically justifiable. In addition, we explore the legitimacy of providing CAM and conventional therapies that have been demonstrated to be effective only by virtue of the placebo effect.