Prescribing placebos ethically: the appeal of negatively informed consent.

Kihlbom has recently argued that a system of seeking negatively informed consent might be preferable in some cases to the ubiquitous informed consent model. Although this theory is perhaps not powerful enough to supplant informed consent in most settings, it lends strength to Evans' and Hungin's proposal that it can be ethical to prescribe placebos rather than "active" drugs. This paper presents an argument for using negatively informed consent for the specific purpose of authorising the use of placebos in clinical contexts.