What are the risks of a gastrografin enema? ?

They usually explain the risks to you and make you sign the waiver they tell you that that white milky stuff that you're drinking is mildly radioactive and could increase your risks of colon and stomach cancer.

Beside that there is not much of a risk it's not likely to cause an allergy it's just water a little bit of barium sulfate add some magnesium citrate to make you poop.

After you go to the bathroom it leaves your intestinal tract mildly radioactive so that they could take a detailed x-ray

The risks are the same as with a barium enema (or any enema, for that matter.) Gastrogafin is merely a different type of contrast material/dye. It's water soluble (barium isn't) and is used when a bowel perforation is suspected, bcuz you wouldn't want barium leaking out into the peritoneal sac.