Complementary and alternative medicine (CAM) is becoming a significant factor in the arena of cancer care. There is an increasing body of research along with widespread popularity and use by patients with cancer. This article reviews current knowledge about the worldwide use of CAM in the treatment of cancer and patients' motives and reasoning for this use. Clinical research in CAM cancer treatments and physicians' attitudes toward this popular trend among patients with cancer are discussed as well. The physician-patient communication and its relevance to CAM use is emphasized. A step approach is suggested for primary care physicians including the discussion of CAM in the management of cancer in order to enrich the physician-patient dialogue and improve the quality of the clinical encounter.