Harvard Men's Health Watch

The powerful placebo

Modern physicians practice evidence-based medicine. Whenever possible, they use the latest scientific studies to plan their tests and guide their treatments. Even so, medicine is an art as well as a science. Trust, confidence, and belief are important parts of the therapeutic relationship, and they can have a powerful effect on healing.

Scientists understand the importance of expectations and beliefs. They know that some patients feel better after they take a medication, even if the drug turns out to be entirely ineffective. Doctors call it the "placebo effect." It's well-named, since the term is derived from the Latin placere, or "to please."

When researchers want to find out if a new medication is safe and effective, they test it against a placebo, an inert, inactive "dummy" pill that looks, tastes, and smells exactly like the test medication. In the best experiments, the patients are randomly assigned to take either the placebo or the test pill, and neither the volunteers nor their doctors know which is which until the study is over. In medical lingo, these studies are called placebo-controlled, double-blind randomized clinical trials.

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