‘therapy’ is a legal concept of considerable import, traditionally juxtaposed with, but separate from, research and also, to some degree, marking the boundaries of legitimate medical intervention. the recent case of simms highlighted these issues, in addition to which novel clinical interventions were the subject of specific recommendations in the bristol royal infirmary inquiry report. this article subjects the notion of therapy to analytical scrutiny and considers the extent of proper clinician discretion to innovate and, albeit much more superficially, how medicine should itself evolve. it advocates a new, more (patient) protective model which should generate confidence in the ethical character of contemporary innovatory practices.