Defibrotide is a polydeoxyribonucleotide salt that shows antithrombotic activity through a suggested profibrinolytic mechanism. To study the effectiveness of defibrotide in atherosclerosis, we evaluated the fibrinolytic and coagulation behavior in normal subjects and patients with atherosclerotic disease, before and after single or repeated intravenous defibrotide infusion. A significant shortening of the ELT was found in all subjects. However, since neither t-PA increase nor PAI decrease was observed, we suggest that the profibrinolytic response to defibrotide may be due to mechanisms other than t-PA stimulation. Our results provide further evidence for the usefulness of defibrotide antithrombotic prophylaxis in atherosclerosis.