I sometimes suspect that everything that I learnt at medical school will one day be proved to have been wrong. When it comes to therapeutics and management, then few drugs or theories ever survive the onslaught of new research. This is almost certainly a good thing, however frustrating it might seem when we have to try to keep up. We need high quality evidence to ensure that we don’t keep on making the same mistakes with ever increasing confidence. Simply believing that something works, and having stories of grateful patients, can never be sufficient.