A placebo ( pluh-SEE-boh) is a medicine or treatment intended to appear genuine to its recipient, but which has no pharmaceutical effect. Common placebos include inert tablets (like sugar pills), inert injections (like saline), sham surgery, and other procedures. Placebos are used in randomized clinical trials to test the efficacy of medical treatments. In a placebo-controlled trial, any change in the control group is known as the placebo response, and the difference between this and the result...
