Disseminated intravascular coagulation (DIC) is caused by a variety of underlying disorders, and criteria for diagnosis are not well defined. However, the most helpful are a low platelet count, positive plasma protamine test, and fibrinogen and fibrin degradation product levels viewed in the context of the patient's underlying disease. The cornerstone of therapy is prompt treatment of the underlying disease and elimination of the trigger mechanism. Additional treatment must be individualized, and generalizations are difficult to make. However, if the patient has low hemostatic factors and is actively bleeding or requires an invasive procedure, then replacement with the appropriate hemostatic factors should be tried. Heparin is indicated in patients with purpura fulminans and venous thromboembolism, but there is little evidence that heparin reverses organ dysfunction associated with DIC. In addition, heparin is also probably indicated in patients with retained dead fetus and hypofibrinogenemia prior to induction of labor, excessive bleeding associated with a giant hemangioma, and neoplastic disease, particularly promyelocytic leukemia. Although the use of heparin in acute forms of DIC remains controversial, the majority of studies suggest that it is not helpful. The role of antithrombin III (AT-III) concentrates is unknown, but they theoretically may be helpful when DIC is associated with very low AT-III levels, as is seen in liver disease.