The safety and efficacy of streptokinase (STK) (Kabikinase; Keatings) in restoring vessel patency in 70 patients with acute myocardial infarction are reported. Return of vessel patency occurred more frequently (76%) in patients receiving STK than in patients in a control group (12%) (P = 0.001). The main complication was bleeding, which invariably resulted from invasive procedures. Dangerous dysrhythmias were uncommon and no fatalities were caused by STK administration. It is recommended that thrombolytic therapy be started as early as possible in patients with acute myocardial infarction, who can then be referred to centres equipped for coronary angiography for further management. Unnecessary invasive procedures should be avoided.