Increasing use of complementary and alternative medical (CAM) therapies by patients, health care providers, and institutions has made it imperative that physicians consider their ethical obligations when recommending, tolerating, or proscribing these therapies. The authors present a risk-benefit framework that can be applied to determine the appropriateness of using CAM therapies in various clinical scenarios. The major relevant issues are the severity and acuteness of illness; the curability of the illness by conventional forms of treatment; the degree of invasiveness, associated toxicities, and side effects of the conventional treatment; the availability and quality of evidence of utility and safety of the desired CAM treatment; the level of understanding of risks and benefits of the CAM treatment combined with the patient's knowing and voluntary acceptance of those risks; and the patient's persistence of intention to use CAM therapies. Even in the absence of scientific evidence for CAM therapies, by considering these relevant issues, providers can formulate a plan that is clinically sound, ethically appropriate, and targeted to the unique circumstances of individual patients. Physicians are encouraged to remain engaged in problem-solving with their patients and to attempt to elucidate and clarify the patient's core values and beliefs when counseling about CAM therapies.