While aspirin has been a major advance in preventing vascular events in high risk patients, it fails to prevent approximately three-quarters of such events. Combined data from animal studies and randomized trials support the potential increased benefit of thienopyridines when added to aspirin. Clopidogrel has been shown to be an effective and safe agent of this class. There is also a need for easier to use therapies in managing patients with acute coronary syndrome (ACS) both in the acute phase and long term. CURE is a large international study to determine if acute and long-term treatment with the combination of clopidogrel and aspirin is superior to aspirin alone in patients with acute coronary syndrome.