[en] BACKGROUND: Excessive mediastinal bleeding after cardiopulmonary bypass is one of the most frequently reported complications of cardiac operations. Appropriate treatment requires a rapid and effective diagnostic work-up, based on the knowledge of the pathophysiology induced by cardiopulmonary bypass. METHODS: Possible causes, diagnostic methods available, and therapeutic approaches are reviewed in the light of the literature published on excessive bleeding after cardiac operations. RESULTS: When bleeding is massive (> 250 to 300 mL/h for the first 2 hours, > 150 mL/h thereafter), immediate surgical reexploration is mandatory. When bleeding is less important (50 to 150 mL/h), the decision to reoperate should be based on the presence of hemodynamic compromise or a suspected surgical cause. Otherwise, coagulation testing should allow the correction of hemostatic defects as appropriate with protamine, platelet concentrates, fresh frozen plasma, desmopressin, or antifibrinolytics. Hypothermia and hypotension should be corrected and a trial of positive end-expiratory pressure may be considered if diffuse mediastinal oozing (especially from the bed of the mammary artery) is suspected. CONCLUSIONS: A protocol is suggested to guide treatment, taking into account the rapidity of blood loss and the suspected underlying cause.