When should doctors nudge their patients towards the treatments they think are best? If the nudge is compatible with the patient giving informed consent, then the nudge could be permissible. To be compatible with informed consent, the nudge must, at minimum: (1) not make the patient’s understanding worse and (2) not make it hard for the patient to resist consenting. Arguably, many nudges will meet these criteria. However, since unjustified nudging, in this context, would also be unjustified paternalism, the permissibility (...) of nudging hinges on whether it is justified. Perhaps surprisingly, this is often not the case. In situations where the best medical judgement does not conclusively favour a single course of action but there are multiple viable options, patient preference ought to be the deciding factor. In such contexts of preference-sensitive care, there is no good reason for doctors to nudge the patient towards a specific course of action, and hence, nudging is unjustified. Outside such contexts, nudging may be both justified and permissible. (shrink)