The preventive effect of fibrin sealant on post-operative formation of peritoneal adhesions was investigated in rats. Intraperitoneal adhesion formation was induced with a standardized, sutured defect in the peritoneum. The influence of sealant thickness and lifetime was evaluated by application of a thin and a thick layer of fibrin sealant containing high or low concentration of antiplasmin. Assessment of adhesion formation one week post-operatively showed significantly less adhesion to the defects covered with the thick layer of sealant having high or low antiplasmin concentration as compared with defects having only a thin sealant layer or control rats without sealant.