Thrombus on the atherosclerotic plaque is mainly responsible for acute coronary syndromes. Antithrombin therapy continues to be the mainstay of the therapy defeating thrombus. Up-to-date antithrombin therapy consists of vitamin K antagonists, unfractionated and low molecular heparins, direct thrombin inhibitors and selective inhibitors of factor Xa. Today, none of these drugs is effective enough in every aspect. The need for new antithrombin drugs, as well as the need for new antiplatelet drugs which can be safely and effectively used to- gether with other antithrombin drugs, persists.