Interest in complementary and alternative medicine (CAM) continues to grow at an exponential rate despite the advances made by conventional medicine. Complementary and alternative medicine use is increasingly manifest across a wide range of health care settings, and is particularly prevalent in cancer and palliative care. In these arenas, patient groups and self-help organizations play a significant supportive role. There is evidence that they are a key informative and pragmatic resource in the provision of CAM services to patients. However, there is a significant paucity of research dealing with the functional aspects of these groups and the way in which they advocate, promote and supply CAM. In this paper we provide a critical review of the literature pertaining to themes around CAM provision and cancer care, and suggest that for a more complete picture of the field, the impact of group mediation of CAM needs to be addressed, and attention focused on the social and interactional dynamics that underpin these groups and organizations.