A multicentre controlled trial was conducted on 383 patients to compare the effectiveness of flurbiprofen (100 mg/day) and an ergot derivative in preventing cerebral infarction. The end-point of the trial was recurrence within 3 years of treatment with one or the other drug of a fatal or non-fatal cerebral infarction. Only those patients who had already experienced an established and disabling ischaemic accident in the carotid or vertebro-basilar territory were included; 88% of these entered the trial less than 6 weeks after the accident. Sixty-one patients had recurrent cerebral infarction during the 3-year observation period: 22 in the flurbiprofen group and 39 in the ergot derivative group (p less than 0.02 log rank test adjusted by centre). The actuarial recurrence rates in the two groups were 13% and 21% respectively. These results concur with those of other trials involving aspirin to demonstrate the value of antiplatelet aggregation drugs in the secondary prevention of atherothrombotic cerebral infarction.