Enhanced CT is to inject a large dose of iodine-containing contrast agent from the vein for a short time before CT scanning, so the side effects are mainly caused by both the injection method and the iodine agent, as follows: 1. In the injection method, the amount of contrast agent used is usually about 70-120ml, with an injection rate of about 2.5ml/s. Therefore, most people will experience a feverish feeling when injecting the drug, which is a normal phenomenon and does not need to be nervous. With the end of drug injection, this feeling will disappear. 2. The side effects of iodine are mainly allergy and nephrotoxicity. The non-ionic iodine contrast agent used for enhanced CT has a high safety level and few adverse drug reactions occur, but a few patients may have allergic reactions due to special constitution or certain unpredictable factors, but most of them are mild allergic reactions. Most of them are mild allergic reactions, such as rash and gastrointestinal reactions, which can be relieved by the application of anti-allergic drugs. However, very few people have heavy allergic reactions, such as laryngeal edema, tracheal spasm, and shock, which require resuscitation and infusion therapy, or even life-threatening. People who are allergic to iodine contrast agents should not have enhanced CT, although the percentage of allergy is small and most people can do it safely. Nephrotoxicity is due to the fact that iodine contrast agent is mainly metabolized by the kidneys in the human body, so patients with abnormal kidney function are prohibited or cautious to do enhanced CT examinations. Patients who cannot eat can be hydrated by infusion to promote the excretion of contrast agent from the body.