Although treatment refusal is an infrequent occurrence in paediatric oncology, it is an important issue that threatens the ongoing therapeutic relationship between the health-care team and families. While there are good reasons to support the decision-making authority of parents in the medical setting, parents' rights in this respect are not absolute. Fortunately, most disagreements between clinicians and parents regarding treatment decisions for children are resolved within the health-care team/family dyad or with the objective advice of other clinicians or clinical ethics services. The increasing appeal of 'natural therapies' and unsubstantiated confidence with which they are prescribed may lead to more frequent refusal of conventional, evidence-based oncology treatment in the future. The harm principle may assist paediatric oncologists in the difficult task of determining when it is justifiable to refer a case for judicial intervention.