Anaphylactoid reactions with gastrointestinal contrast media.

Significant anaphylactoid reactions to gastrointestinal contrast media are rare. Whether a patient who is atopic or has asthma is predisposed to these reactions is speculative. The rare patient who previously had a severe allergic reaction to such a product probably should not undergo a subsequent examination with a similar agent. The American College of Radiology classification of contrast media side effects can also be applied to the gastrointestinal contrast media.