As with all anticoagulants, drotrecogin alfa (activated) is associated with a risk of severe bleeding. During the infusion period in the PROWESS trial, the bleeding rates were 2.4% in the drotrecogin alfa (activated) group versus 1.0% in the placebo group (P = 0.024). The risk of bleeding was fairly constant across most subgroups. However, severe thrombocytopenia (< 30,000/mm 3 ) was commonly associated with serious bleeding and intracerebral hemorrhage.