The anxiolytics are a group of CNS-active agents which in the last 25 years have played an ever-increasing role in the physician’s armamentarium. They are mild sedatives with pronounced activity in anxiety, tension, and neuroses, including psychosomatic disorders. They generally do not act in psychoses, but are sometimes used in combination with neuroleptics to relieve anxiety in depressed psychotics. Several chemically completely unrelated classes of compounds are known to possess antianxiety properties and are discussed below. Although this chapter deals mainly with anxiolytics used in the United States, the sections on benzodiazepines (B.IV and B.V) include drugs used solely in other countries.