[en] Venous thromboembolic disease contributes to morbidity and mortality in certain groups of hospitalized patients, particularly those who have undergone surgery. Although principles of treatment have changed relatively little during the past 20 years, significant advances have been made in the diagnosis of deep vein thrombosis (DVT). Venography, once the only reliable diagnostic technique, has been largely replaced by noninvasive tests: impedance plethysmography, venous Doppler, ¹²⁵I-radiofibrinogen-uptake test, and phleborheography. Virchow's triad of stasis, vessel injury, and hypercoagulability remains a valid explanation of the pathogenesis of thrombus formation, but laboratory and clinical data have refined our knowledge of how these factors interact to result in clinically significant disease. Knowledge of the natural history of venous thrombosis, plus heightened awareness of the long-term morbidity and expense associated with the postphlebitic syndrome, have led to increased interest in preventing DVT. Clinically and economically, venous thrombosis is best managed by prevention. 61 references