It is my belief that placebo controlled studies are necessary and ethical, yet should not be the “proof” that a drug/ medical-device combination is effective. This is due to the many curiosities that still surround the idea of a placebo and its potential to alter both the subject’s perception and physical wellbeing. Many underestimate the power of the mind and its ability to heal through sheer belief that and the many beneficial outcomes that come from simply being in a positive mindset. It is interesting to note in an experiment where patients are given a placebo, whether they are told it is fake or not, a given percentage will still have positive physiological responses. This phenome must be accounted for when analyzing the final data. An addition, contrary to what merzkrashed mentioned above, placebos can cause negative responses. There have been studies where patients thought they were being exposed to an (false) irritant and have broken out in the expected reaction. Read more in below reference.