MarginalRevolution has a discussion of the surprising lack of evidence for most medical procedures, and, the more general, primitive state of medicine.
I would find the above somewhat hard to believe, had I not recently had a little medical scare myself. I was surprised at how eager doctors are to treat symptoms without any clue as to underlying causes. In fact, 3 out of 4 specialist doctors that I saw wanted to operate on me (!), a serious operation which in hindsight would have fairly radically altered my life and in retrospect would have been completely unnecessary. Only after working through medical journals and research myself and after meeting with a young research doctor did I figure out that the problem would simply run its course and subside – which it did.
(Incidentally, if you think that this somehow radically alters my views on evidence-based management – it does not – more later on this matter.)