Glutaraldehyde-preserved pericardium was used to close the pericardial sac after open heart surgery in 100 patients. The indication for implantation of a xenologous pericardial patch was always the lack of autologous pericardium to close the pericardial sac without significant tension. This was mainly due to previous use of an autologous pericardial patch or implant of an extracardiac conduit for the repair of congenital cardiac disease (n = 82) and reoperation after primarily open pericardium (n = 10). In this series with a mean follow-up of 3.1 months (range 1 to 12 months) no infection of the xenologous equine pericardial implant and no mediastinitis occurred. Even in cases of early reoperation (n = 6) for bleeding or tamponade there was no patch infection (implants left in situ). At medium-term reoperation in 3 cases, after a mean interval of 115 days, adhesions between the epicardium and the xenologous equine pericardial patch were graded mean 1 (blunt adhesions) on a scale of six (minimum = 0, maximum = 5). In another series of re-dos for coronary bypass surgery with pericardium primarily left open, the mean grade of adhesions formed in the anterior epicardial space was 2.7 (severe). The histology of explanted equine pericardium showed no new vessels and no in-dwelling organization. Although the follow-up is relatively short, this material appears to offer a valid non-adherent substitute to separate the posterior sternal surface and the cardiac cavities. Its application improves the safety at resternotomy.