Stroke is a leading cause of death and disability. Although advances are being made in the treatment of acute ischemic stroke, its prevention is equally as important. Identification and management of risk factors are essential. Medical therapy is also helpful in the secondary prevention of ischemic stroke. There are currently four platelet-antiaggregating agents used to prevent ischemic stroke: aspirin, aspirin plus dipyridamole, clopidogrel, and ticlopidine. The relevant studies proving their efficacy are noted, as are some of their similarities and differences. The use of warfarin is also discussed.