A placebo is a fake or inactive treatment that is designed to resemble, as closely as possible, an active medication. It is usually given to one group in a clinical trial while another group receives the actual drug being tested, in order to determine if the real drug has any effect over and above what would be expected from the placebo itself. The word "placebo" comes from the Latin phrase "I will please," indicating that it is intended to have no therapeutic effect but to create a belief or expectation of improvement.