Advanced liver disease and low ascitic fluid protein concentration have been identified as risk factors for spontaneous bacterial peritonitis in cirrhosis. Moreover, renal impairment and hyponatremia increase mortality rate of this infection. Aims: To investigate if oral administration of norfloxacin prevents the first episode of SBP, hepatorenal syndrome and improves survival in cirrhotic patients with ascites and low protein concentration in ascitic fluid (<15 g/L) and at least one of the following inclusion criteria: functional renal failure (serum creatinine ≥ 1,2 mg/dl or BUN ≥ 25 mg/dl), hyponatremia (serum sodium ≤ 130 mEq/L) or advanced liver disease (Child ≥ 9 points with serum bilirubin ≥ 3 mg/dl). Methods: Prospective, multicenter, randomized, double-blind placebo controlled trial comparing oral norfloxacin (400 mg/d; n=35) with placebo (n=35).

Inclusion Criteria:

• Age 18-80 years, protein concentration in ascitic fluid < 15 g/L and at least one of the following: serum creatinine ≥ 1.2 mg/dl or BUN ≥ 25 mg/dl, serum sodium ≤ 130 mEq/L or severe liver failure as defined by a Child-Pugh score ≥ 9 points and a serum bilirubin ≥ 3 mg/dl.

Exclusion Criteria:

• Previous history of spontaneous bacterial peritonitis or of norfloxacin prophylaxis, allergy to quinolones, hepatocellular carcinoma, organic renal failure and HIV infection