The patency rate and reocclusion incidence were studied in 97 patients following vascular surgery necessitated by occlusion in the aortoiliac or femoropopliteal regions or both. Forty-nine patients were treated orally with a combination of acetylsalicylic acid and dipyridamole (1050 mg + 150 mg/day) and 48 patients with the haemorheologically active agent pentoxifylline (1200 mg/day, Trental 400 tds.) for uniform periods of 6 months. Reocclusion occurred in 10 patients receiving ASAD and in 5 patients receiving pentoxifylline. Adverse reactions were recorded in 12 patients with ASAD (discontinuation in 11) and in 3 patients with pentoxifylline (discontinuation in 2). Patency and tolerability rate were significantly superior in those patients treated with pentoxifylline, suggesting that the combination of haemorheological effects with antihaemostaseological and antithrombotic properties offered by pentoxifylline may be of benefit in the prevention of reocclusion after vascular surgery.