X-ray contrast agents are substances used in medical imaging to enhance the visibility of internal structures during X-ray examinations. These agents work by absorbing X-rays more than surrounding tissues, allowing doctors to see organs, blood vessels, and other structures more clearly. Common types include iodine-based and barium-based agents, each suited for different types of imaging. When a patient undergoes a procedure like a CT scan or fluoroscopy, the contrast agent is typically administered orally or intravenously. This helps highlight areas of interest, making it easier to diagnose conditions such as tumors, blockages, or infections.