Long-term use of the peritoneum as a dialysis membrane results in progressive irreversible dysfunction, described as peritoneal fibrosis. Oxidative stress during peritoneal dialysis has been established in many studies. Generation of reactive oxygen species (ROS) by conventional peritoneal dialysis solutions, regardless of whether produced by high glucose, angiotensin II, or glucose degradation products may be responsible for progressive membrane dysfunction. The well-known antioxidant molecule N-acetylcysteine (NAC) is capable of direct scavenging of ROS. The aim of the present study was to investigate the effect of NAC therapy on both progression and regression of encapsulating peritoneal sclerosis (EPS). We divided 49 nonuremic Wistar albino rats into four groups: Control group-2 mL isotonic saline intraperitoneally (IP) daily for 3 weeks; CG group-2 mL/200 g 0.1% chlorhexidine gluconate (CG) and 15% ethanol dissolved in saline injected IP daily for a total of 3 weeks; Resting group-CG (weeks 1 - 3), plus peritoneal resting (weeks 4 - 6); NAC-R group-CG (weeks 1 - 3), plus 2 g/L NAC (weeks 4 - 6). At the end of the experiment, all rats underwent a 1-hour peritoneal equilibration test with 25 mL 3.86% PD solution. Dialysate-to-plasma ratio (D/P) urea, dialysate white blood cell count (per cubic milliliter), ultrafiltration (UF) volume, and morphology changes of parietal peritoneum were examined. The CG group progressed to encapsulating peritoneal sclerosis, characterized by loss of UF, increased peritoneal thickness, inflammation, and ultimately, development of fibrosis. Resting produced advantages only in dialysate cell count; with regard to vascularity and dialysate cell count, NAC was more effective than was peritoneal rest. Interestingly, we observed no beneficial effects of NAC on fibrosis. That finding may be a result of our experimental severe peritoneal injury model. However, decreased inflammation and vascularity with NAC therapy were promising results in regard to membrane protection.