Peritoneal fibrosis is one of the major causes of technical failure in patients on peritoneal dialysis (PD) for long period of time. Although the exact mechanisms of peritoneal damage during PD still remain unclear, generation of reactive oxygen species may be responsible for progressive membrane dysfunction. N-acetylcysteine (NAC)is a powerful antioxidant shown to protect peritoneal fibrosis in peritoneal dialysis animal model. In this study the researchers investigated the hypothesis that NAC protect peritoneal membrane damage.

N-Acetylcysteine (NAC) is known to be relatively safe and beneficial in peritoneal dialysis patient at a dose of 1200 mg per day. Patients will be randomly assigned to NAC and control group and prescribed according to the protocol. At 2 and 6 month, Peritoneal equilibrium test (PET) will be performed with blood sampling.

Inclusion Criteria:

• Maintenance peritoneal dialysis at least 3 months
• Patients who are able and willing to understand, sign and date an informed consent document, and authorize access to protected health information

Exclusion Criteria:

• Episode of peritonitis at least 3 months
• Episodes of admission due to other disease at lease 3 months
• Liver disease
• Allergic history with N-acetylcysteine