An X-ray contrast agent is a substance used in medical imaging to enhance the visibility of internal structures during an X-ray examination. These agents work by absorbing X-rays more than the surrounding tissues, making organs and blood vessels appear clearer on the images. Common types include iodine-based and barium sulfate agents, which are administered orally or intravenously, depending on the area being examined. The use of X-ray contrast agents helps doctors diagnose various conditions, such as tumors, blockages, or infections. While generally safe, some patients may experience allergic reactions or side effects, so it's essential to inform healthcare providers of any known allergies before the procedure.