Antibiotic associated colitis due to Clostridium difficile is a common infection associated with significant morbidity. In severe cases, Pseudomembranous colitis (PMC) may be associated with intraperitoneal fluid accumulation. Howwver, the characteristics of the liquid are seldom described. This case report describes PMC patients who were presented with low serum-ascites albumin gradients (SAAG)and neutrocytic ascites, without evidence of infectious, malignant, or inflammatory peritoneal disease. The characteristics of their fluid specimens and the possible pathogenic mechanisms are discussed. These findings suggest that PMC without bowel perforation or spontaneous bacterial peritonitis. ( Korean J Gastrointest Endosc; 21: 568-571)