In the case of acute coronary syndrome with prolonged ST elevation on ECG showing an acute coronary obstruction, the urgent institution of fibrinolysis is a widely validated treatment. Since the first placebo controlled studies with streptokinase until the development of bolus administration rt-PA varieties, fibrinolytic agents have lowered mortality. Associated anti-thrombotic drugs are multiplying in parallel. Their association is recognised as necessary in order to avoid early reocclusions which worsen the prognosis of infarction, the fibrinolysis triggering a harmful prothrombotic effect, notably due to the clot thrombin re-exposed during thrombolysis. Aspirin has an essential place formally demonstrated in ISIS 2. Non-fractionated heparin has more complex effects and its administration protocol in association with fibrinolysis has recently been reviewed with a reduction in dosage because prolonged clotting times during fibrinolysis have provoked a distinct increase in the risk of intracranial haemorrhage. The low molecular weight heparins seem to have become the adjuvant treatment of choice following publication of the ASSENT-3 trial. Pentasaccharide seems attractive. The place of hirudine and its derivatives in the acute phase of MI appear limited after the results of the HERO-2 trial, associating hirulog and streptokinase, with the earlier studies also having been disappointing. The GPIIbIIIa blockers in association with a half dose of fibrinolysis do not aggravate the intracerebral haemorrhagic risk before 75 years old and clearly reduce hospital morbidity in infarction, at the price however of an increase in transfusions.