For decades management of acute myocardial infarction (AMI) consisted of bed rest, oxygen, prevention for thromboembolic complications, and treatment of arrhythmias and heart failure. In the last years a more aggressive treatment of AMI has been developed, based on the following three basic principles: (1) Mortality of patients with AMI is determined by the infarct size and the degree of left ventricular dysfunction. (2) The time interval between the onset of coronary occlusion and any intervention to limit infarct size is brief and takes usually not more than three to four hours. (3) After the acute phase of infarction a lot of patients remain at high risk of fatal coronary events, i.e. reinfarctions. The angiographic findings during the first hours of AMI showed in about 80% of patients an obstructive coronary thrombus and led to efforts to dissolve the offending thrombi. The demonstration that coronary thrombi can be lysed in about 80% of cases within 60 minutes after the intracoronary injection of thrombolytic agents (streptokinase or urokinase) has boosted the reperfusion therapy in AMI in the hope that ischemic myocardium might be salvaged. Intracoronary infusion of thrombolytic agents however, can be applied only in a minority of patients with AMI because coronary angiography and a skilled team of investigators are required, therefore a short-time intravenous high dose streptokinase infusion was developed. In the meantime two large double blind randomized trials (ISAM and GISSI) could demonstrate a reduction in hospital mortality in AMI especially by early treatment with intravenous streptokinase. Conventional thrombolytic agents produce a systemic lytic state with the possibility of hemorrhage, therefore recombinant tissuetype plasminogen activator (rt-PA) and two other drugs, acylated streptokinase and pro-urokinase, were developed with the aim of inducing coronary thrombolysis without severe systemic lytic state, but the efficacy of these new drugs remains to be demonstrated in randomized trials versus conventional thrombolytic agents.(ABSTRACT TRUNCATED AT 250 WORDS)