Large clinical trials have demonstrated the clinical effectiveness of therapy with inhibitors of the platelet surface-membrane glycoprotein IIb-IIIa receptor in a broad range of patients with ischemic heart disease. Abciximab, a platelet glycoprotein IIb-IIIa receptor blocker, is associated with improved long-term prognosis in patients who require angioplasty and stent placement. Severe bleeding from abciximab use is an uncommon event. We describe a patient with severe pulmonary hemorrhage after treatment with abciximab, and discuss predisposing factors and protamine infusion in this potentially fatal complication.