We present 3 patients with intraabdominal infections. The diagnostic difficulties are caused by the atypical presentation of many of these infections. Fever, deterioration of general condition and loss of appetite and weight are uncharacteristic signs that lead to a delay in correct diagnosis and the beginning of therapy. In the following paper we discuss septic pylephlebitis, spontaneous bacterial peritonitis and renal abscesses as important representatives of intraabdominal infections.