Intravascular contrast media are used for a variety of imaging studies. The classification of contrast media can be made from many different perspectives (e.g. ionic vs. nonionic, monomers vs. dimers, low osmolality vs. high osmolality, etc.). Reactions to contrast media are generally classified as either systemic (idiosyncratic) or chemotoxic. Idiosyncratic systemic reactions occur independently of dose or concentration of the agent, chemotoxic effects related to dose, the molecular toxicity and the physiochemical characteristics of contrast agents. Contrast media produce a peripheral vasodilatation, which is often perceived by the patients as a sensation of heat and pain, hypotension and release of histamine from the mast cell, and causes hives, bronchospasm, coughing and anaphylactoid reaction. The best treatment for contrast media reaction is prevention. Adequate screening of patients may identify individual patients who should not receive contrast media for various reasons (e.g. previous significant adverse reaction to contrast media, allergies, asthma, cardiac dysfunction, renal insufficiency etc.). The goal of nursing care in patients with intravascular contrast media should be to utilize these agents appropriately and properly so that imaging studies are optimized and risk to patient is minimized.