Iodine contrast agent is usually completely excreted within 24 hours, but the rate of excretion depends on the function of the kidneys and varies among individuals. If the kidneys are functioning normally, most of the iodine contrast agent is completely excreted within 24 hours through metabolism in the body; if the kidneys are weak, the excretion time will be relatively longer. Therefore, the use of iodine contrast agent is generally not recommended for people with poor kidney function. It should be noted that iodine contrast media may cause allergic reactions of varying degrees. Moderate allergy may cause hives, laryngeal edema, bronchospasm, etc. Severe allergy may lead to pulmonary edema and cardiac arrhythmia. Therefore, before using iodine contrast agent, it is necessary to strictly exclude contraindications and have the appropriate precautions before taking the contrast examination. It is recommended to drink more water after use to help the discharge of contrast agent.