Background: Spontaneous bacterial peritonitis (SBP) is a serious complication in patients of cirrhosis with ascites and may occur despite antibiotic prophylaxis. Small bowel dysmotility and bacterial overgrowth have been documented to be related to SBP. Aims: To investigate whether addition of prebiotic plus probiotics (synbiotics) to norfloxacin enhances the efficacy of norfloxacin in prevention of SBP in high risk patients with ascites.