Past and present of ''what will please the lord'': an updated history of the concept of placebo.

In ecclesiastic tradition the term ''Placebo'' indicated the promise to please the Lord in medieval prayer. The expression ''Placebo Domino'' (''I shall please the Lord'') constituted the beginning of a famous passage of a V century A.D. translation of the Bible. It was in the second half of the XVIII century that the word Placebo became an integral part of the medical-pharmacological vocabulary, and in fact Quincy's Lexicon (1787) defined it as a remedy used more to please than to heal people. For centuries placebos have been considered precious deceptive therapies and, until 1945, they were generally considered to be morally useful management tools. At the end of World War II it was clear that a critical evaluation of the function of placebos was needed to shed some light on their real role. Following this methodological call, in the years following different studies on placebos were proposed, and in 1955 HK Beecher published in the JAMA a paper, ''The Powerful Placebo'', in which he concluded that it was evident that placebos had a high degree of therapeutic effectiveness. Recent evidence points to the fact that, on the contrary, placebos do not have major clinical effects and that the limits of their application should be fully acknowledged.