High levels of use of complementary and alternative medicine (CAM) have been consistently reported amongst cancer patients over recent years. This is occurring in the context of an apparent increase in sources of information on therapeutic alternatives and a growth in the range of those claiming professional expertise in the field. To date there has been little research on patient experience of discussions about CAM with biomedical cancer specialists in this increasingly complex social environment. This paper addresses three issues: patient experience with cancer specialists; the significance of that experience for patient engagement with CAM; and the nature and significance of inter-professional dynamics. It draws on the results of a qualitative study with cancer patients in the UK. In-depth interviews with 80 purposively sampled patients, incorporating a range of disease types and stages, were conducted. Patients reported three main types of approach by oncologists: explicit or implicit negativity; supportive ambivalence; and, pragmatic acceptance. Crucially, patients' accounts suggest that the type of approach adopted influences (though does not determine) patient action. Specialist cancer nurses emerged as potentially powerful mediators between oncologists and patients. Despite the apparent potential for influence from multiple information sources and 'experts', on the basis of this study we would argue that oncologists remain crucial to patient engagement with CAM. However, this is not to argue that the influence is a simplistic one. Where patient and medical perspectives diverge, strategic alignment with specialist nurses may help patients make choices which conflict with perceived advice.