We speak of placebo effect when a substance that has no pharmacologic effect gives a therapeutic result. Fever, pain and vomiting are ways to get better but have an associated cost. The pain related to an ankle sprain stops us from walking and is the price to avoid making things worse. Fever kills bacteria, but makes us use up a lot of resources. These ways to get better are triggered when control mechanisms responsible for overseeing aspects such as our general health, how dangerous the illness is etc., decide that the cost is worth the benefits. Control mechanisms have been selected by evolution to do precisely this evaluation otherwise we would not be here. But now things are different. Modern man is educated, strong and healthy, the outcome of a disease can be foreseen and the control mechanisms could actually ‘run a few more risks’ than compared to a million years ago. This would save on the costs as well. The problem is that the control mechanisms require a very long time to re-set and so ‘get-better mechanisms’ that are exaggerated for the circumstances continue to be triggered. In this situation of modern reality and excessive prudence on the part of control mechanisms the placebo finds its space. A substance with absolutely no medical effect tricks the control mechanism saying: “Don’t worry I’ll look after matters and so you need not trigger fever, vomiting etc.” Obviously, if these are truly not necessary you live better without fever, vomiting etc. and the patient thinks he has been cured when instead a white lie did everything. It’s an irrational procedure, but not necessarily a wrong one as it corrects the pessimism of a control mechanism that is not keeping up with the times.