Gas in the portal venous system is a rare non-specific condition. It has many causes, but most commonly it is associated with intestinal necrosis. In a group of 6 patients authors found a necrotic bowel in 4 cases. Other 2 causes were blunt abdominal trauma and polypectomy. Two patients with bowel necrosis died, 2 survived after urgent laparotomy. Two patients without bowel necrosis were successfully treated conservatively. The most sensitive diagnostic method is CT, ultrasonography and simple abdominal film has a lower sensitivity. The amount of gas in the portal venous system and its distribution do not correlate with the patient’s prognosis. We must always consider the history and clinical state of the patient. In ambiguous cases it is necessary to consider bowel necrosis, which is the most common and the most serious cause of this sign.

        Key words: portal venous gas – intestinal necrosis – computed tomography – ultrasonography – simple abdominal film