For patients with ischemic stroke or transient ischemic attack caused by atherothromboembolism, immediate and long-term aspirin reduces the relative risk of recurrent stroke, MI, and death attributable to vascular causes. Oral anticoagulation is not more effective than aspirin. Long-term clopidogrel reduces the relative risk of stroke, MI, or vascular death by about 9% (0.3% to 16.5%) compared with aspirin. Any long-term benefits of clopidogrel combined with aspirin, compared with aspirin or clopidogrel alone, appear to be offset by increased major bleeding. The combination of aspirin and extended-release dipyridamole reduces the relative odds of stroke, MI, or vascular death by about 18% (odds ratio 0.82, 0.74 to 0.91) compared with aspirin alone without causing more bleeding. Cilostazole reduces the risk of stroke, MI, or vascular death by 39% compared to placebo. A large clinical trial comparing clopidogrel with the combination of aspirin and dipyridamole, in >20 000 patients with recent (<120 days) atherothrombotic ischemic stroke, is expected to report in 2008. Emerging antiplatelet therapies presently being evaluated for secondary prevention of atherothromboembolism include other P 2 Y 12 ADP receptor antagonists (prasugrel, cangrelor, AZD 6140), thromboxane receptor antagonists (eg, S18886 - terutroban), and thrombin receptor (PAR-1) antagonists (eg, SCH530348).