The aim of this study was to determine the efficacy of oral antibiotics in the treatment of severe infections in cirrhosis. Twenty-two patients (17 males, 5 females) with spontaneous bacteremia (n = 7) or bacterial peritonitis (n = 15) were treated with oral pefloxacin 400 mg per 24 hr alone (n = 1) or in combination with another oral antibiotic, trimethoprimsulfamethoxazole (n = 13), amoxicillin (n = 6), cefadroxil (n = 2), or metronidazole (n = 1). In patients with spontaneous bacteremia, all organisms were found to be sensitive to oral antibiotics, and a favorable response was elicited in 6 out of 7 (86 p. cent) within 3 days (mean) of treatment. In patients with spontaneous peritonitis, ascitic fluid cultures were positive in 11 cases, and organisms were sensitive to pefloxacin in 9 out of 11 cases. A favorable response was elicited in 13 out of 15 within 2 to 8 days of treatment. Fourteen patients died (64 p. cent), 3 of infection (bacteremia n = 1, peritonitis n = 2), and 11 patients of causes unrelated to infection, mainly variceal hemorrhage, hepatorenal syndrome or hepatocellular carcinoma, although the clinical symptoms of infection were controlled. One-year survival was 57 p. cent in patients with bacteremia and 33 p. cent in those with bacterial peritonitis. Oral treatment was well tolerated in all patients. We suggest that most bacteremia and spontaneous bacterial peritonitis in cirrhotic patients can be treated with oral antibiotics. In some patients, this may be accomplished on an out patient basis.