Placebo (lat. placebo - I'll love) - indifferent substances used in the clinical trial of the drug for the exclusion of psychotherapeutic effect. They are given the greatest similarity with subjects drugs in color, taste, smell; they are used in the same dosage form (tablets, pills and other). In order to avoid erroneous conclusions sometimes use the double-blind breakdown, in which neither the patient nor the medical staff, including a doctor, don't know when applied a placebo. This is particularly important when evaluating the data, based mostly on subjective sensations.