Conventional benzodiazepine anxiolytics cause unwanted daytime sedation which increases the risk of behaviorally toxic reactions and may interfere with the therapeutic process. Recently a number of 'serotonergic' anxiolytics have been developed and most are under investigation in ongoing clinical trials. One, buspirone, has emerged into clinical practice. It is said to possess a much lower sedative potential than benzodiazepines and to be a safer and more effective anxiolytic for that reason. An extensive literature concerning buspirone's behavioral effects generally supports these assertions. Nonetheless, studies conducted to date are of variable quality; have revealed some adverse effects of buspirone; and, have left several critical questions unanswered. The present review seeks to provide a comprehensive picture of the drug's known effects on human performance and related variables, such as sleep and subjective reactions. It discusses deficiencies of particular studies and the limitations of present knowledge. Finally it suggests how future studies might be better designed to provide information of greater clinical relevance.