In a group comprising a total of 217 patients with a recent myocardial infarction, who were treated with streptokinase the authors provided evidence that early recanalization of the coronary occlusion occurred after superselective intracoronary administration in 81 and 83% of the patients. After intravenous streptokinase administration they recorded early recanalization in 62%. They found a significant diminution of the infarction focus and improved left ventricular function, as compared with patients treated in the "classical" way by antiarrhythmic drugs, beta-blockers and vasodilatating drugs. The follow up of some other indicators is also in favour of significant improvement after thrombolytic treatment--thrombi in the left ventricle, cardiac decompensation, development of an aneurysm, myocardial rupture. Conversely an argument against thrombolytic treatment are more frequent haemorrhagic complications--16%. However, in these complications no deaths were recorded nor the need of an operation or discontinuation of maintenance anticoagulant treatment. In reperfused patients no hospitalization mortality was recorded. Reocclusions occurred most frequently during the first four weeks after treatment and only after intracoronary administration--10%. According to the authors this is due to residual stenoses more serious ones, 75% of the lumen--the higher incidence of reocclusions in significant stenoses is statistically evident. The only prevention of reocclusions is immediate follow up of PTCA after intracoronary thrombolysis. The intravenous administration of streptokinase in myocardial infarctions is according to the authors a safe method and they recommend its use in all coronary units in the CSSR.