What Is the Placebo Effect?

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.

In-Depth Explanation of the Placebo Effect:

• The Healing Power of Placebos
• Is Every Placebo the Same?

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.

_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}