The present invention is directed to therapeutic methods using IL-6 antagonists such as antibodies and fragments thereof having binding specificity for IL-6 to prevent or treat thrombosis in diseases associated with abnormal blood coagulation or fibrinolysis. In preferred embodiments these patients will comprise those exhibiting elevated D-dimer or other coagulation cascade related proteins and optionally will further exhibit elevated C reactive protein prior to treatment. The subject therapies also may include the administration of other actives such as chemotherapeutics, anti-coagulants, statins, et al.