Placebo

A placebo is an inert or fake drug with no active ingredients but considered crucial to the conduct of many scientifically-based clinical trials. It is given to one group of study participants in a blind or double-blind trial to allow researchers to objectively test and evaluate the effectiveness of a new treatment against a controlled group.

A placebo is designed to look the same as the active medication or treatment, and is administered in the same way as the real drug, but has no effect on the body. At the beginning of the trial, participants are randomly divided into two groups. One of these groups is given the real treatment, while the other is given a placebo. When neither group knows which they have been given, this is called a "blind study". When neither group nor the researchers know which has been given, this is called a "double-blind study".

All partakers are told what they may be likely to expect from the active treatment and if a placebo is invloved it is generally required that they are told they may be given an inactive treatment. In blind studies, however, participants do not know if they are using the real or dummy treatment. Hence, both groups will have a similar state of mind. This may reduce bias cause by the "placebo effect". That is, any improvement that is measured, observed, or felt by the participant after the placebo is given.