This paper concerns a practice that is sometimes encountered in the treatment of patients with mental illness: the use of placebo for purportedly therapeutic purposes. It will consider the lawfulness of that practice under domestic law; and suggest that previous attempts to perform such an analysis may be flawed. It will argue that existing statutory restrictions may apply to - and prohibit - therapeutic placebo administration, and will conclude with a brief analysis of the possible impact upon such administration of the Human Rights Act 1998. The word 'placebo' is here used in the sense of "a pill, medicine, procedure etc., prescribed more for the psychological benefit to the patient of being given a prescription than for any physiological effect".' It does not describe the use of any similar substance in the testing of new drugs (nor, to acknowledge every facet of the formal definition, does it connote either vespers for the dead or an eighteenth century sycophant). Furthermore, it is assumed that the use of placebo is founded upon a clinical assessment that such is the preferable course, for to deny a patient substantive medication that might carry a therapeutic benefit would be to invite litigation, primarily, though by no means exclusively, under the domestic tort of negligence.