title: Why are placebos used, and why do they sometimes work?
mesh_terms: D001921:Brain / Q000378:metabolism; D002986:Clinical Trials as Topic; D003213:Conditioning, Psychological; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D015990:Placebo Effect; D010919:Placebos / Q000627:therapeutic use*; D012718:Set, Psychology
chemical_list: D010919:Placebos