Placebo
An inactive substance or treatment that has no biological effect. Placebos are used in studies that aim to test the effectiveness of new drugs or treatments. Any treatment accepted in the belief that it will relieve symptoms or cure disease is likely to bring about improvement of symptoms of some disorders. This is known as the placebo effect. When new drugs are being tested a ‘placebo-controlled’ study is carried out as follows: the number of patients is randomly divided into two groups, with the first group being given the test drug and the second, or control, the group being given the best drug and the second, or control, the group being given a placebo which looks and tastes exactly the same. Neither the researchers nor the patients know who is taking drugs or placebo until the study has been completed. In this way, the researchers can properly determine the effectiveness of the drug against mere confidence that something is being done. Such is the power of placebo effect that in some complaints it produces as much relief as theoretically effective drugs.