Take a fictitious case, the patient X. Several times a day for several days, causes pain, which is controlled by doses of morphine. Until the last day of the experiment. Those 24 hours without knowing Mr. X, morphine was replaced by saline quite innocuous. It seems incredible, but this solution has the same effect as morphine and the pain disappears.
This is what is known as the placebo effect. Before the arrival of drugs in the twentieth century was the most potent weapon against the disease medicine. Crocodile dung, oil worm lizard blood and to be touched by the King were medicines used between the XVI and XIX century. Since the publication in 1955 of The Powerful Placebo HK Beecher, it was recognized that 35% of patients with a wide variety of diseases could be treated only with placebo. In later studies, we have seen that can operate at 70% and even 100% of cases.
