Placebo is a substance or a compound that is visually made to resemble a drug or medicine but functionally has no pharmacological effect. It is used in clinical trials to eliminate the impact of bias. . For instance, in order to show the effectiveness of an anti-diabetic drug, some people are administered with the original drug and are given placebo treatment in the same condition. In this way, researchers can evaluate the effectiveness of that drug by comparing the effect of the drug in selected patients to that of placebo treated patients.