Thrombotic occlusion of coronary arteries is the reason of most acute coronary syndromes. A significant role in their prevention and therapy is taken by antiplatelet therapy. Acute coronary syndrome justifies also the use of anticoagulation therapy, name by heparin. The adjuvant therapy by means of heparin in thrombolysis seems to be necessary especially when alteplase (t-PA) is used. Peroral anticoagulants represent a further therapeutical procedure in patients with coronary ischaemia. Regarding the increased risk of bleeding, the cost and difficulties coinciding with therapy by cumarine derivates, the antiplatelet therapy is currently preferred. Cumarine derivates, however, should be used in patients with simultaneous atrial fibrillation, venous thromboembolism and it should be considered in patients with heart failure and pre-thrombotic states. Studies aimed at the assessment of the role of low-molecular heparin in acute coronary ischaemia currently take place. Encouraging results are gained from experience with high effective direct inhibitors of thrombin (e.g. hirudin) and antagonists of glycoprotein IIb/IIIa. It seems that they soon will find justification in the therapy of arterial thrombosis. Interesting field of the research is represented by the studies which compare low doses of acetylosalicylic acid with low doses of cumarine derivates. (Ref. 43.)