Background: To ensure safety and effectiveness of cancer management, it is important for physicians treating cancer patients to know whether their patients are using CAM and if so, why. Objective: We 1) discuss physicians’ ethical and legal obligation to discuss CAM use in an oncology setting, and 2) provide practical advice on how patient –provider communication about CAM can be improved.Results: Physicians have both ethical and legal obligations to their patients, including the obligation to respect patient autonomy. This extends to patients’ CAM use and needs to be addressed beginning early in the patient-provider relationship. As lack of education in this field and lack of time during patient consultations are barriers to talking with patients about CAM, we provide resources to facilitate such discussions. These include suggestions on how to discuss the topic as well as a wide range of information sources.Conclusion: Discussing CAM with patients is the physician’s responsibility and will facilitate evidence-based, patient-centred cancer care. Keywords: cancer, complementary and alternative therapy, physicians, patients, communication