In my job, professor of complementary medicine, I meet many clinicians who do the strangest things, for instance, administer unproven or disproven treatments (UDTs). I have often asked myself: why? For many years, I have been pondering this seemingly simple question, and gradually I became convinced that there is not one single reason but at least four themes that we need to consider. Desperation is clearly one of them. In fact, it is the one that clinicians tend to offer most readily: ‘For many patients there is no treatment that is evidence-based,’ they claim thus justifying their use of UDTs. When I then question which conditions they might be referring to, the response tends to be more hesitant. Eventually the argument turns out to be that ‘many patients suffer from undiagnosable conditions’. I have always been puzzled by this claim, mainly because it does not portray my own impressions or recollections of being a clinician. Undiagnosable patients do, of course, exist but they are not in the majority. Even if I accept that many patients belong to this category, I remain sceptical. In particular, I wonder whether these patients are truly undiagnosable or perhaps only not properly diagnosed, and whether there really is no evidence-based treatment to help them – not even to alleviate symptoms regardless of any diagnosis. Furthermore, I ask myself whether some of these undiagnosed patients really require medical treatment at all, considering the risk of medicalizing what might only be minor reductions of wellbeing. Crucially I am puzzled why these clinicians tend to administer UDTs to so many of their patients – even to those that do have a well-established diagnosis. In any case, I question that one uncertainty (unidentified diagnosis) can be eliminated by adding a further uncertainty (unproven therapy). Belief is another powerful reason for using UDTs. In complementary medicine, belief supremely reigns over evidence. As an example, consider the physician who uses spiritual healing despite the fact that there is overwhelming evidence disclosing it as hocus pocus.1 But belief in a therapy clearly can overpower even the most solid evidence. This is perhaps understandable – we are all only human. But it is also regrettable. Medicine has been dominated by dogma for centuries, and progress was made only when science replaced creed.2 If we allowed our beliefs to get the better of us, I fear, we would be regressing back towards the dark ages. I am therefore convinced that replacing evidence with belief is a disservice to our patients. Incompetence is, in my experience, a third and common reason for using UDTs. Some clinicians seem to find it difficult to discriminate between scientific evidence and promotional pseudo-evidence. Medical schools have in the past not always been the best places for acquiring the skills of critical thinking, and institutions for educating other healthcare professionals (e.g. the colleges training practitioners of complementary medicine) may well be worse. Many aspects of clinical medicine are, of course, hugely complex and often hard to comprehend. It is undoubtedly easier to adopt the simplistic concepts of, for instance, ‘energy healing’ which do not require any detailed understanding of pathophysiology, pharmacology, et cetera. Disappointment is another prominent reason for employing UDTs. Many healthcare professionals get disillusioned with the current healthcare business, the dominance of ‘big pharma’, the lack of time and empathy they are able give to their patients, and so on. Some of these clinicians therefore feel the need to look elsewhere and are somehow able to find entirely new realms of healing. These seem to make patients happy and might even render life as a clinician more satisfying. It seems to matter little that, in this fantasy world, drugs are replaced by vague concepts of ‘energy’ and diagnostics are substituted by intuition. What should, however, matter to any responsible clinician is that, in this fantasy world, patients are not treated with the most effective treatments available to them.