In studies about new medicines, researchers usually give one group of patients the medicine that is
designed to treat an illness. They give another group of
patients a placebo, which is taken the same way as
the medicine but does not actually contain the
ingredients of any medicine. Different medicines are
tested in different experiments, but the placebos
usually contain the same non-medical ingredients. I
both groups of patients are healed, then researchers
cannot be sure whether the medicine caused
improvement, but if the group given the medicine is
healed while the group given the placebo remains ill,
researchers can conclude that the medicine causes
the illness to go away.
In medical experiments, which group receives
placebos?
the experimental group
the control group
both the experimental and control groups
neither the experimental nor control group