Description: The financial and social costs of Alzheimer's disease are staggering. In the United States, the disease accounts for about $100 billion per year in medical and custodial expenses, with the average patient requiring an expenditure of about $27,000 per year for medical and nursing care. In addition, 80 percent of caregivers report stress, and about 50 percent report depression. This article reviews the pathophysiology of Alzheimer's disease, evidence for the efficacy of various pharmacologic treatments, and guidelines for the use of drug therapy in patients with this devastating disease.