Although dipyridamole was identified as a potential antithrombotic agent many years ago,1its effectiveness as a single agent in secondary prevention of arterial thrombosis in man has never been proven in properly conducted clinical trials with sufficient power. In many clinical trials it has been tested in combination with aspirin, and until recently meta-analyses have failed to show any significant benefit of the combination of aspirin and dipyridamole beyond that shown with aspirin alone.2,3