A placebo refers to a treatment that is given to the control group in a clinical drug trial. In order for researchers to figure out how well the experimental treatment works, it needs to be compared to a control. In some cases, the control group may not receive anything at all. They may be given a sugar pill or some saline. In other cases, the control group may be given the currently accepted standard which the experimental drug needs to be compared against. Placebos come in many shapes and forms, and it is important to make sure the control group does not know they are getting the placebo. This is one of the reasons why blinding might be used in a clinical trial.