Milk just like barium based drink

Cost-Effectiveness and Patient Tolerance of Low-Attenuation Oral Contrast Material: Milk Versus VoLumen -- Koo et al. 190 (5): 1307 -- American Journal of Roentgenology

For years, countless people have had to force down about 1,200 cc of a barium contrast drink before having CT scans of their abdomen and pelvis to diagnose bowel disorders and abnormalities. The barium coats the insides of the esophagus, stomach and intestine, appearing dark while the intestinal wall appears brighter. The contrast from the barium allows radiologists to better visualize the bowel wall and more clearly delineate the bowel cavity and soft tissue. Barium drinks, however, can come with unpleasant side effects like constipation, diarrhea, nausea and cramping. The acidy-burning taste of the chalky, milky liquid can make getting it down one of the most unpleasant parts of the diagnostic test.

Children especially balk at drinking the barium–based drinks.

Clever researchers at St Luke’s-Roosevelt Hospital in New York City thought , "hmmmm - constipation, diarrhea, nausea and cramping?.....same syptoms many people have if they drink milk" They wondered if milk might work just as well.

And it does!

No statistically significant differences were seen between whole milk and VoLumen with respect to degree of bowel distention and mural visualization for all segments of bowel studied