Behavioral symptoms are an integral component of Alzheimer's disease (AD) and an important cause of failure of home care. Well-chosen pharmacologic and psychosocial treatments can improve many of the distressing problem behaviors that occur in the course of the disease and, in some cases, may delay institutionalization. However, controlled trials remain scarce, and prediction of treatment outcome for individual patients is still uncertain at best. Recent improvements in the characterization of behavioral syndromes in AD hold promise for increasing the specificity of treatment choice and the predictability of response. This article reviews features of the major behavioral problems associated with AD and evidence for the effectiveness of existing treatments. We argue that the origins of behavioral disturbances include both intrinsic neurobiological aspects of the disease and environmental provocations, and present an approach to treatment decision- making that respects both the clinician's need to intervene to reduce suffering and the limitations of current knowledge.