A recent report has highlighted the high incidence of medical errors in clinical practice and the important fact that errors are associated with increased mortality. This issue is now being examined closely in the field of thrombolytic therapy for acute myocardial infarction. Numerous trials have found that the dose of the thrombolytic agent is closely related to outcome, with too low a dose associated with lower rates of infarct-related artery patency and higher doses associated with increased bleeding and intracranial hemorrhage. Thus, the "therapeutic window" for thrombolytic therapy is small, and the potential for adverse outcome from dosing errors is high. In the Global Use of Strategies To Open occluded arteries (GUSTO)-I trial, 13.5% of patients treated with streptokinase and 11.5% of patients treated with tissue plasminogen activator (t-PA) were subjected to a medication error (e.g., incorrect dose or infusion length). Most importantly, 30-day mortality was significantly higher in patients with medication errors: For t-PA dosing errors, mortality was 7.7% versus 5.5% for patients who received the correct t-PA dose (p<0.001); findings were similar for streptokinase. More recent data from the Intravenous n-PA for Treatment of Infarcting Myocardium Early (InTIME)-II trial and other studies showed that use of a bolus thrombolytic agent reduced the rate of medication errors. Thus, use of the simpler bolus thrombolytic agents may improve overall clinical outcome.