Abstract Fatal pulmonary embolism is a major cause of postoperative death. When no prophylaxis is given in general surgery, it has a frequency of about 1%. Apart from the immediate risk to life, one must also consider the late sequelae of extensive deep vein thrombosis—swelling of the legs, varicose veins, ulceration and other trophic changes which represent an equally distressing situation. Recently, three large-scale surveys have been published, where the data of over 100 randomized controlled clinical trials of prophylaxis against venous thromboembolism has been analysed. The purpose of this talk is to provide an overview of the currently available prophylactic methods analysed in these surveys, with an aim to define a policy for preventing venous thromboembolism, with particular emphasis on the surgical patients. There is evidence suggesting that the frequency of fatal pulmonary embolism can be reduced by such prophylactic remedies as low-dose heparin, dextran, the combination of dihydroergotamine plus heparin, and low molecular weight heparin.