Peritoneal adhesions prevention. Neurokinin-1 receptor antagonistBackground: The fibrinolytic activity plays an important role in Peritoneal Adhesions (PA) development.It´s well known that de substance P decreased the fibrinolysis by binding the neurokinin-1 receptor, improving the PA formation.Objectives: To evaluate the effectiveness of intraperitoneal treatment with a Neurokinin-1 receptor antagonist (NK-R1A) in peritoneal adhesion prevention in animal model.Materials and Methods: In 40 male wistar rats, PA were induced, and then randomly assigned to 2 groups: A group treated with Aprepitant (NK-R1A), and a control group.The animals were killed at 7 or 14 postoperative day, and the number, severity and histopathology of PA were evaluated.Results: NK-R1A decreased the number (40% less) and severity (p = 0.001) of PA when compare to control group.The NK-R1A group had less PA in manipulated and no manipulated organs during surgery.Besides presented less fibrosis (p = 0.001), less inflamation (p = 0.005) and less vascular proliferation (p = 0.047) than control group.Conclusions: The NK-R1A is effective as in PA prevention.