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Definition: A placebo, as used in research, is an inactive substance or procedure used as a control in an experiment. The placebo effect is the measurable, observable, or felt improvement in health not attributable to an actual treatment.

When a treatment is based on a known inactive substance like a sugar pill, distilled water, or saline solution rather than having real medical value, a patient may still improve merely because their expectation to do so is so strong. To eliminate the effect of positive thinking on clinical trials, researchers often run double-blind, placebo-controlled studies.

For An In-Depth Explanation Of The Placebo Effect:

The Healing Power of Placebos

Is Every Placebo The Same?

The Mysterious Placebo Effect

Fast Facts About The Placebo Effect:

• The word placebo literally means “I will please” in Latin.


• The first known double-blind placebo-controlled trial was done in 1907.


• The FDA doesn't require that a drug study include a placebo control group, however, the placebo-controlled trial has long been the standard.


• The NIH is funding several studies related to the placebo effect.
  

Also Known As: Placebo, Placebo response, Power of suggestion

Common Misspellings: plasebo, placeboo, placebo affect

Examples: The patient thought she was feeling better, but was it real or the placebo effect?

_{Sources: Placebo Effect, Robert Todd Carroll, The Skeptic's Dictionary, Skepdic.com, The Mysterious Placebo Effect, by Carol Hart, American Chemical Society, Modern Drug Discovery, July/August 1999: The Healing Power of Placebos, by Tamar Nordenberg, FDA Consumer magazine January-February 2000}