A great many patients coming to a clinic for the first time are already using one or more drugs. The physician must be aware of this, not only for the purpose of prescription, but also in determining the validity of patient responses. He should be aware, too, of the correlation between demographic data and drug effect. I f a drug is indicated, the therapist must consider, in addition to questions of potency, side effects and possible habituation, what he hopes to achieve through therapy. This paper provides a brief clinical evaluation of psychoactive drugs and their interaction with such non-drug variables as setting, expectation, placebo response, therapist attitude, and social class.