BACKGROUND. In contrast with current standard regimens, it seems more appropriate to tailor thrombolytic therapy to individual patient characteristics. A proposed model for such tailored therapy is based on individual assessment of benefits and risks of thrombolytic therapy, taking into account the response of individual patients to the therapy given. METHODS AND RESULTS. Potential benefits of thrombolysis in individual patients can be predicted by use of demographic patient characteristics (age, sex, history of previous infarction) together with indicators of the ischemic area at risk (total ST segment deviation) and treatment delay. Using these parameters, the number of "lives saved" by thrombolytic therapy for specific patient characteristics can be estimated. Similarly, the risk of intracranial hemorrhage during thrombolytic therapy can be estimated from the patient's age, blood pressure at admission, and body weight. Depending on benefit/risk estimates, a choice can be made between regimens with high, medium, or modest thrombolytic efficacy. Continuous multilead ECG ischemia monitoring and rapid assays of myocardial proteins in serum can be used to assess the occurrence or absence of reperfusion and to detect signs of reocclusion. Such data help to decide whether thrombolytic therapy should be continued or intensified or might be discontinued in individual patients before the total standard dose has been administered. Such tailored reduction of the total thrombolytic dose will reduce the risk for bleeding complications in some of the patients. CONCLUSIONS. The concept of tailoring thrombolytic therapy and the models presented for benefit/risk assessment should be tested in clinical studies and may subsequently help the physician to select the optimal approach in individual patients.