The use of thrombolytic therapy has dramatically altered the treatment of acute myocardial infarction and is rapidly spreading from large medical centers to community hospitals throughout the country. The widespread use of thrombolytic therapy will benefit a wide range of people, but the potential risks of this form of therapy must be understood. Hemorrhage is one of the major risks of thrombolytic therapy. This review will focus on the data available from a number of recent, large trials of thrombolytic therapy for acute myocardial infarction with respect to laboratory parameters that may predict hemorrhagic complications and/or help with their management. We will discuss both conclusions drawn from currently available data and address future research directions.