Patients receiving barium sulfate or iodine-based contrast materials may experience - Diarrhea or constipation - Nausea and vomiting - Mild skin rashes or redness - Agitation or confusion - Difficulty breathing or swallowing If you experience any of these symptoms, notify your doctor as soon as possible. If you have experienced these symptoms as a result of contrast dye in the past, be sure to let your imaging technician and doctor know when booking your scan.