◊ Patients who have been given a placebo that they think is a real drug may feel better because they believe that they are getting actual medicine. The improvement that they experience in their health is called the placebo effect. Placebos are also used in tests to compare the effect of a real drug with a substance that does not have any physical effect.病人把安慰剂当作药物服用之后可能产生良好的反应，这是因为他们以为自己服用了真正的药物。这种健康状况的改善称为“安慰剂效应”。安慰剂也用于测试，以比照实际药物的效应。