The ESPRIT trial addresses the problem that aspirin, the standard therapy for secondary prevention of vascular complications after a transient ischaemic attack (TIA) or ischaemic stroke of arterial origin, reduces the risk of serious vascular events by only about 13%. Anticoagulants may be an alternative, as these have proved highly efficacious in trials after myocardial infarction and after cerebral ischaemia with atrial fibrillation. After cerebral ischaemia of presumed arterial origin, high-intensity anticoagulation (INR 3.0-4.5) is not safe, but the value of anticoagulation with an INR between 2.0 and 3.0 is still unknown. Secondly, a recent, large trial showed that the combination of aspirin and dipyridamole prevents more major vascular events than aspirin alone, but several earlier trials did not find such an advantage. In ESPRIT, patients with a TIA or minor ischaemic stroke (Rankin grade </=3) will be randomized between oral anticoagulation (INR 2.0-3.0), the combination of dipyridamole (400 mg daily) plus aspirin (in any dose between 30 and 325 mg daily) and aspirin only. Primary outcome is the composite event 'death from all vascular causes, non-fatal stroke, non-fatal myocardial infarction or major bleeding complication', whichever occurs first. Outcome assessment will be blinded. The recruitment of a total of 4,500 patients from more than 10 countries is planned; the mean follow-up will be 3 years.