Oxidative stress has been implicated in intraabdominal adhesion formation. Substance P, a neurokinin-1 receptor (NK-1R) ligand, facilitates leukocyte recruitment and reactive oxygen species (ROS) generation. We have shown in a rat model of adhesion formation that intraperitoneal administration of a NK-1R antagonist at the time of abdominal operation reduces post-operative adhesion formation. Thus, we determined the effects of NK-1R antagonist administration on peritoneal leukocyte recruitment and oxidative stress within 24 hrs of surgery. Adhesions were induced in Wistar rats randomly assigned to receive the antagonist or vehicle intraperitoneally. Peritoneal tissue was isolated at 2, 4, 6 and 24 hours after surgery for analysis of the oxidative stress biomarkers 8-isoprostanes (8-IP), protein carbonyls, NADPH oxidase, myeloperoxidase (MPO) and ICAM-1 and VCAM-1 mRNA. Total antioxidant capacity of peritoneal fluid was also determined. MPO, NADPH oxidase, 8-IP and protein carbonyl were elevated (p < 0.05) by 6 hours. ICAM-1 mRNA was elevated (p < 0.05) by 2 hours while VCAM-1 levels decreased (p < 0.05) at 24 hours. The NK-1R antagonist delayed the MPO rise and reduced (p < 0.05) 8-IP levels by 6 hours, and ICAM-1, VCAM-1 and protein carbonyl at 2 hours. The antagonist also increased (p < 0.05) the antioxidant capacity of peritoneal fluid at all time points. These data further support a role for oxidative stress in adhesion formation and suggest that the NK-1R antagonist may limit adhesions, in part, by reducing postoperative oxidative stress through an inhibition of neutrophil recruitment and an increase in peritoneal fluid antioxidant capacity.