Impregnated graft is frequently used for operations of the large vessels and the usefulness is known to everybody, however, it entails a risk of causing serious inflammatory reaction after surgery. This inflammatory reaction presents difficulties in differentiation from graft infection and can impede postoperative management by physical effects due to exudates of plasma components and pleural effusion. We report two cases of severe inflammatory reactions caused by an impregnated graft after total aortic arch replacement. Case 1: A 77-year-old woman suffered from left prolonged pleural effusion for four weeks since the 15th postoperative day. Because the pleural effusion seemed to be transudate and caused declines of serum albumin and electrolytes, recruitment of these was needed for improvement of the patient's general condition. Case 2: A 70-year-old man with severe chronic pulmonary emphysema had an uneventful postoperative course, however, on the 9th postoperative day, went into cardiac tamponade in several hours. We performed an emergency operation to save the life of the patient when we found a little effusion in the cardiac sac. It was clarified that the effusion was aseptic and resulted from inflammatory reaction due to an impregnated graft. In a condition that a capacity of the pericardial sac was reduced by chronic pulmonary emphysema, only a little fluid might cause a repid progress of cardiac tamponade.