Objective: This study was to evaluate the efficacy of the hyarulonic acid (HA) bioabsorbable membrane combined use with both expanded-polytetrafluoroethylene (ePTFE) and autologous pericardium for preventing postoperative pericardial adhesions. Methods: The HA bioresorbable surgical membrane (Seprafilm, Genzyme, Cambridge, Mass) was used with either ePTFE or autologous pericardium in an experimental pericardial adhesion model. Twenty-four beagle dogs were classified as follows; Group A (n 5 6): ePTFE only, Group B (n = 6): Seprafilm 1 ePTFE, Group C (n = 6): autologous pericardium only, Group D (n = 6): Seprafilm 1 autologous pericardium. Pericardial adhesions were evaluated at necropsy at 4, 8, and 12 weeks. The tenacity of adhesion was graded by macroscopic examination, and the adhesion tissue thickness was analyzed microscopically with an image processing program. The regeneration of mesothelial cells on neo-tissue fibrils were immunohistochemically studied. Results: In groups B and D, the adhesions were significant lower compared with those of control groups in the tenacity (Group A vs B: 2.5 +/- 0.55 vs 1.5 +/- 0.55, P < 0.05; Group C vs D: 3.2 +/- 0.75 vs 0.33 +/- 0.52, P < 0.01) and the tissue thickness (Group A vs B: 30.4 +/- 12.9 vs 10.3 +/- 4.42, P < 0.01; Group C vs D: 22.6 +/- 11.5 vs 4.96 +/- 4.87, P < 0.01). Immunohistochemically, a single layer of mesothelial cells were regenerated on the surface of neo- tissue fibrils in HA treated groups. Conclusion: The combined use of Seprafilm with either ePTFE or autologous pericardium effectively reduced the formation of pericardial adhesion.