placebo

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placebo A treatment which has no effect, and is administered to a control group in experimental research, in place of a treatment whose effects are being studied. This usually happens only in medical research; in social research, control groups are rarely offered a placebo experience or treatment.

In the medical context, a substance lacking known pharmacologically active ingredients is given to the sick in order to please them; that is, for possible beneficial effects arising from faith in the powers of treatment (the placebo effect). Placebos are also widely used as controls in evaluating the therapeutic efficacy of the active components of new drugs. Conventionally, the experimental treatment is given to cases selected at random, with the ineffective placebo given to all other cases, even though they are suffering from the same illness. In the ‘double blind’ situation, even the person administering the treatments does not know which is which, as the medicines are made to look the same, to prevent him or her inadvertently communicating their knowledge to recipients.

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