In general, placebos can be classified as ‘pure’ or impure.’ Pure placebos refer to inert substances such as starch, lactose, saline, talc, or dextromaltose, but impure placebos have known pharmacological activities.Typically, placebos are used in clinical trials as a control intervention to evaluate the potential efficacy and safety of a novel treatment.Often considered the ‘gold standard’ for evaluating the efficacy of a pharmacological intervention, these trials provide the best possible opportunity to determine whether an active treatment is effective.