“At least treatment x does not harm my patient.” How often do clinicians think along these lines? In my field of complementary/alternative medicine, it is arguably the most common reason for using this or that therapy: there is usually little “hard” evidence to suggest harm (by “harm” I mean a negative effect on the disease, not a simple adverse effect). So, if treatment x does not make the condition worse and the patient is keen to try it, we may well decide to condone its use. There …