The use of heparin and warfarin in the treatment of venous thromboembo
lism has been revolutionized by the findings of clinical trials perfor
med over the past decade. This article addresses some unanswered quest
ions regarding the treatment of venous thromboembolism that are the su
bjects of current clinical trials, such as the optimum duration of ora
l anticoagulant therapy in patients with idiopathic or recurrent deep
vein thrombosis and the role of low-molecular-weight heparin in the sh
ort-term and longterm treatment of venous thrombosis.