I'm having a CT scan done of my abdomen and pelvis done this week to see if a hernia has come back, why do I need to drink two bottles of contrast?

2 See Ur Intestine. A ct of the abdomen can be very helpful for diagnosing recurrent hernias. An important part of the study is to look at the intestine relative to the hernia. Contrast in the intestine makes the interpretation of these films much easier.