In the practice of medicine it had been long understood that, as Ambroise Paré (1510–1590) had expressed it, the physician's duty was to "cure occasionally, relieve often, console always" ("Guérir quelquefois, soulager souvent, consoler toujours"). Accordingly, placebos were widespread in medicine until the 20th century, and were often endorsed as necessary deceptions.
According to Nicholas Jewson, eighteenth century English medicine was gradually moving away from a model in which the patient had considerable interaction with the physician – and, through this consultative relationship, had an equal influence on the physician's therapeutic approach. It was moving towards a paradigm in which the patient became the recipient of a more standardized form of intervention that was determined by the prevailing opinions of the medical profession of the day.
Jewson characterized this as parallel to the changes that were taking place in the manner in which medical knowledge was being produced; namely, a transition from "bedside medicine", through to "hospital medicine", and finally to "laboratory medicine".
The last vestiges of the "consoling" approach to treatment were the prescription of morale-boosting and pleasing remedies, such as the "sugar pill", electuary or pharmaceutical syrup; all of which had no known pharmacodynamic action, even at the time. Those doctors who provided their patients with these sorts of morale-boosting therapies (which, while having no pharmacologically active ingredients, provided reassurance and comfort) did so either to reassure their patients while the Vis medicatrix naturae (i.e., "the healing power of nature") performed its normalizing task of restoring them to health, or to gratify their patients' need for an active treatment.
In 1811, Hoopers Quincys Lexicon–Medicum defined placebo as "an epithet given to any medicine adapted more to please than benefit the patient".
Early implementations of placebo controls date back to 16th-century Europe with Catholic efforts to discredit exorcisms. Individuals who claimed to be possessed by demonic forces were given false holy objects. If the person reacted with violent contortions, it was concluded that the possession was purely imagination.
Use of the placebo effect as a medical treatment has been controversial throughout history, and was common until the mid twentieth century. In 1903 Richard Cabot concluded that it should be avoided because it is deceptive. Newman points out the "placebo paradox" – it may be unethical to use a placebo, but also unethical "not to use something that heals". He suggests to solve this dilemma by appropriating the meaning response in medicine, that is make use of the placebo effect, as long as the "one administering... is honest, open, and believes in its potential healing power".
John Haygarth was the first to investigate the efficacy of the placebo effect in the 18th century. He tested a popular medical treatment of his time, called "Perkins tractors", and concluded that the remedy was ineffectual by demonstrating that the results from a dummy remedy were just as useful as from the alleged "active" remedy.
Émile Coué, a French pharmacist, working as an apothecary at Troyes between 1882 and 1910, also advocated the effectiveness of the "Placebo Effect". He became known for reassuring his clients by praising each remedys efficiency and leaving a small positive notice with each given medication. His book Self-Mastery Through Conscious Autosuggestion' was published in England (1920) and in the United States (1922).
Placebos remained widespread in medicine until the 20th century, and they were sometimes endorsed as necessary deceptions. In 1903, Richard Cabot said that he was brought up to use placebos, but he ultimately concluded by saying that "I have not yet found any case in which a lie does not do more harm than good".
T. C. Graves first defined the "placebo effect" in a published paper in The Lancet in 1920. He spoke of "the placebo effects of drugs" being manifested in those cases where "a real psychotherapeutic effect appears to have been produced".