Iodine contrast agent, iodine contrast agent, is generally used in CT enhancement examination, angiography, hysterosalpingography, intravenous pyelography, etc. It is widely used clinically and can show the density difference between diseased and normal tissues. If a tumor patient is injected with iodine contrast agent, it can determine whether the lesion tends to be benign or malignant; if there are abnormalities such as cranial arterial vascular or cardiac aortic vascular embolism, iodine contrast agent can also be injected to clarify the location of the lesion and the severity of the disease, which can provide good help for doctors to make a correct diagnosis. Iodine contrast agents are mainly divided into ionic iodine contrast agents and non-ionic iodine contrast agents, which can also be divided into hypertonic, hypotonic or isotonic contrast agents. Currently, iodixanol, iodixanol and iodofol are commonly used in clinical practice. If patients have severe hyperthyroidism or are allergic to iodine contrast agents, they should tell their doctors in advance to avoid allergic reactions. If the patient has poor kidney function, iodixanol can be chosen, which has little damage to kidney function. Iodine contrast agent has certain side effects, mainly is the possibility of allergic reactions, according to the severity can be further divided into mild, moderate and severe, as follows: 1. Mild: mainly manifests as facial flushing, conjunctival congestion, coughing, sneezing, and some patients may also have rash; 2. Moderate: mainly manifests as wet and cold skin, chest tightness, hoarseness, panic, shortness of breath and decreased blood pressure; 3, Severe: mainly refers to anaphylaxis, which can appear as cyanosis of the skin, drop in blood pressure, and even respiratory and cardiac arrest.