The effect of antiplatelet drugs on the fate of Teflon grafts placed at the superior vena cava were examined. Eighty adult mongrel dogs received dipyridamole, dipyridamole depot capsule, or cepharanthin after implantation of Teflon grafts to the superior vena cava. The incidence of graft obstruction was significantly decreased, suggesting that intimal hyperplasia was prevented by administration of antiplatelet drugs. Eighteen patients underwent various kinds of venous revascularization, including the superior caval, innominate, pulmonary, and femoral veins. The long-term outcome of prosthetic reconstruction of the superior vena cava was favorable.