Abstract

A placebo is a sham medical intervention that can produce a placebo effect. Laboratory evidence supports the existence of several mechanisms of placebo effects in both healthy population and patients with a variety of medical conditions. The ethics of placebos have long been debated. However, accumulating ethical concern has arisen from the worldwide use of placebo in randomized control trials (RCTs), which may render their participants without early and optimal treatment. Although the pilgrimage of placebo is still on the way, refinement of controls in RCTs is worth paying new attention to.