Postoperative adhesion (POA) is a common and well-known complication with an estimated risk of 50-100%. The antioxidant effect of n-acetyl-cysteine (NAC) can increase intracellular glutathione levels, thereby reducing adhesion. This study was conducted to compare the outcomes of NAC nanoparticles (Nano-NAC) on intra-abdominal adhesion (IAA) after laparotomy in rat. A total of 25 male Wistar rats were randomized into five groups: 50 mg/kg Nano-NAC, 75 mg/kg Nano-NAC, 150 mg/kg Nano-NAC, NAC and control. During the surgical procedure, some sections (2×2cm) were collected through abdominal midline incision to ensure the infliction of peritoneal damage by a standard adhesion. Macroscopic evaluation was performed on the 14th and 28th day and blood samples were collected to evaluate the inflammatory factor (C-reactive protein) on days 0, 14 and 28. According to the serologic results (CRP test), C-reactive protein was at highest level in 150 mg/kg Nano-NAC and control groups and at lowest level in 50 mg/kg Nano-NAC and 75 mg/kg Nano-NAC groups (p<0.001). The macroscopic evaluation results showed that frequency of adhesion bands was significantly lower in 50 mg/kg Nano-NAC group than the control at the intervals. Results showed that the intraperitoneal administration of lower Nano-NAC dosages (50 and 75 mg/kg) had a major role in the management of postoperative inflammation. Nano-NAC administration was proved feasible, safe and effective in reduction of the C-reactive protein level.