How to know if you have gastrografin allergy?

Prior reaction: the only way to know for sure is if you have had a previous allergic reaction to Gastrografin. Reactions to oral contrast agents are rare.

Iodine allergy: Here is the fda blurb: anaphylactic reactions: anaphylactic reactions, including fatalities, have been reported with the use of gastrografin. Patients at increased risk include those with a history of a previous reaction to a contrast medium, patients with a known sensitivity to iodine, and patients with a known clinical hypersensitivity (bronchial asthma, hay fever, and food allergies). Medical p.

Difficult : Unless one has had an allergic reaction to gastrograffin in the past or trouble with dye studies on the past, it is very difficult to predict if the first exposure will cause a problem.