Some people have reactions to the contrast agent, though the risks are low. Allergic reactions can include hives, itching, nausea, vomiting, headache, and dizziness. There can also be some risk of kidney damage from the dye for people with certain conditions. It helps to talk with your doctor about your health history before using a contrast agent.
If you are pregnant or may be pregnant, you should let your doctor know before having an x-ray. X-ray radiation can be dangerous for a fetus.