Publisher Summary This chapter discusses Radiological contrast media and radiopharmaceuticals. Radiological contrast media such as barium sulfate, barium intravasation, perforation, encephalopathy, granulomatous reactions. There is a discussion about intravascular contrast media, angiography and cardiography, cerebral angiography, digital subtraction angiography and computed tomography, nephrotoxicity, thromboembolic phenomena, thrombocytopenia, interactions and tissue toxicity. The chapter also discusses myelography, discography, bronchography, and hysterosalpingography. Individual contrast media such as iodized oil, sodium ipodate, and Perfluoro-oetylbrnmide (PFOB) have been described. Magnetic resonance imaging media such as gadolinium pentate dimeglumine, radiopharmaceuticals like dipyridamole-thallium imaging and its interaction and thorium dioxide sol (thorotrast) have been described.