Antibiotics for peritonitis are usually broad-spectrum antibiotics, such as cephalosporins like cefoperazone, combined with anaerobic drugs. The antibiotics used for peritonitis need to be selected according to the severity of peritonitis and the severity of the systemic infection. In mild cases of peritonitis, first or second generation cephalosporins may be selected. If the peritonitis is more severe, a third- or fourth-generation cephalosporin or penicillin may be needed. Peritonitis first requires treatment of the primary disease, and when the primary disease is controlled, peritonitis can often be cured.