Side effects that occur after the use of contrast agents include manifestations of allergy, decreased blood pressure, shock, bronchospasm, laryngeal edema, convulsions, and respiratory circulatory arrest. Contrast agents are one of the most commonly used drugs in CT-enhanced and MRI-enhanced scans, and are mainly used for the visualization of blood vessels and organs. Currently, the most commonly used in clinical practice are iodine-containing preparations. The use of contrast media should be accompanied by a doctor and the patient should be observed in the observation room for about 30 minutes, as most of the adverse reactions occur during this period. If there are high-risk factors, such as severe kidney or liver disease, the patient should be kept under observation for a longer period of time. In case of adverse reactions with severe symptoms, such as shock, treatment must be observed in intensive care. Contraindications to contrast application include the presence of iodine allergy or contrast allergy, severe cardiorespiratory insufficiency, uncontrolled severe cardiac arrhythmias, such as ventricular arrhythmias, tachy-type atrial fibrillation, and supraventricular tachycardia, uncorrected hypokalemia, digitalis toxicity, and electrolyte disorders and acid-base balance disorders, severe hepatic and renal insufficiency, and hemorrhagic diseases, such as bleeding and coagulation disorders in patients with such conditions. There is no specific and effective way to prevent side effects from contrast media, but the impact of contrast media side effects can be reduced by using non-ionic contrast media, reducing the amount of contrast media, and changing the way the contrast media is injected.