Twenty healthy volunteers were treated for 3 months with oxpenifylline (200 mg 3-times a day) or a placebo in a controlled double-blind randomized trial. The volunteers taking the oxpenifylline showed a significant increase in their fibrinolytic activity, as assessed by the dilute blood clot lysis time and fibrin plate lysis area, and a significant reduction in their plasma fibrinogen levels. No change was found in the control group. These findings suggest that oxpentifylline may be valuable in the treatment of small vessel occlusive disease associated with lowered fibrinolytic activity and raised fibrinogen levels.