High-dose chemotherapy and autologous stem cell transplantation (ASCT) is used to treat some advanced malignancies. It is a traumatic procedure, with a high complication rate and significant mortality. ASCT patients and their carers draw on many sources of information as they seek to understand the procedure and its consequences. Some seek information from beyond orthodox medicine. Alternative beliefs and practices may conflict with conventional understanding of the theory and practice of ASCT, and 'contested understandings' might interfere with patient adherence to the strict and demanding protocols required for successful ASCT. The present study, conducted in Sydney, Australia, examines narrative-style interviews with 10 sequentially recruited ASCT patients and nine of their carers conducted at the time of transplant and three months later. Transcripts were read for instances of mention of alternative advice, and for instances of contested understanding of information relevant to the transplant. Patients and carer pairs expressed closely concordant views about alternative advice. Five pairs were consulting alternative practitioners. Contested understanding was expressed in four domains-understandings of the transplant itself and its underlying theory, of the relationship between the components of the 'transplant', of the nature and role of stem cells, and of beliefs about bodily function and life-style. Contested understandings of the transplant treatment were expressed as predominantly personal interpretations of orthodox information. Patients and carers seemed to recognise that alternative and conventional systems were discordant, yet they were able to separate the two, and adhere to each practice without prejudicing their medical treatment. A single case of late, post-transplant repudiation of Western medicine is discussed to emphasise some of the possible determinants of dissonance when it does occur. © 2006 Elsevier Ltd. All rights reserved.