A brief history of the word placebo was presented and the placebo effect was defined. Characteristic examples of prescientific medical treatment were described. The following conclusions were reached: The normative history of medical treatment until relatively recently is the history of the placebo effect. Although physicians prescribed what we now know to be useless and often dangerous medications and procedures for thousands of years, they maintained their positions of honor and respect throughout history because they did help their patients. This was possible because of the potent placebo effect. The placebo effect is related to the doctor-Patient relationship and a number of other factors derived from this relationship. The placebo effect is maximized by the closeness of the doctor-patient relationship in psychiatric treatment. Therapeutic efficacy should be studied and evaluated in the light of the methodological principles stemming from this knowledge.Abstract Teaser