The increasing importance of properly controlled drug trials in modern medicine has shown the need for further study of the “placebo response” and the effects of “suggestion”, particularly in the evaluation of the results of treatment of the psychoneuroses. Much of the work on the response to placebos has been done on their deleterious side-effects,i.e., the production of symptoms of various kinds, but some recent investigations have clearly demonstrated the amelioration of symptoms by the administration of placebo.