The use of abciximab, a chimeric monoclonal antibody Fab fragment specific for platelet glycoprotein IIb/IIIa receptors, is associated with improved outcome after angioplasty and stent placement. Major complications include bleeding, but pulmonary hemorrhage has been reported rarely. This study was done to identify patients with pulmonary hemorrhage following abciximab infusion and to define, if possible, any specific risk factors.Retrospective review of institutional coronary angiography and bronchoscopy databases to identify patients who received abciximab and developed pulmonary hemorrhage.Tertiary-care teaching hospital.All patients who underwent coronary angiography and received abciximab between June 1995 and March 2000.None.Seven of 2,553 patients (0.27%) had documented severe pulmonary hemorrhage associated with chest radiographic abnormalities, impaired oxygenation, and the need for blood product transfusions. The initial symptom was hemoptysis in four of the seven patients. There were two early deaths and one late death. No cases of pulmonary hemorrhage were identified in 5,412 patients who underwent coronary procedures without abciximab infusion. No other risk factors predicting hemorrhage were identified.Severe pulmonary hemorrhage is a complication of abciximab use. Although hemoptysis is an important alerting symptom, it may not be present initially and the diagnosis may be missed or considered late, with the potential for inappropriate treatment until the diagnosis is established. Lesser degrees of bleeding are potentially easily missed, and this report should alert physicians to this complication so that it can be considered early in the evaluation of patients presenting with pulmonary events after abciximab use.