Thrombosis is the formation of a blood clot inside a blood vessel, which may cause reduced blood flow to a tissue, or even tissue death. Thrombosis, inflammation, and infections are responsible for >70% of all human mortality. Thrombosis is also the major factor for heart disease and stroke. 500,000 die from thrombosis every year in Europe. Inhibitory treatment of these conditions may also improve the outcomes of several non-fatal diseases. Researchers from Vanderbilt University and Oregon Health & Science University have jointly discovered new monoclonal antibodies that potently inhibit the blood coagulation protein factor XII (FXII), a critical player in the pathway, and anticoagulate blood. This invention provides foundation for commercial development of anti-thrombotic drugs based on new molecular entities.