Iohexol is not a therapeutic drug, so we cannot talk about its efficacy. Iohexol is a contrast agent, which is used in X-ray and CT examinations for intravascular, intravertebral and intracorporeal use. It has an enhancing effect on X-ray and CT scan images and can increase the clarity of CT as well as contrast, thus improving the diagnostic rate. It is mainly used for adult brain imaging and urography and cardiovascular imaging in adults and children. Adverse reactions such as warmth, slight pain, flushing, nausea or vomiting, mild chest pain, itchy skin and rubella may occur during use, and severe allergic reactions may lead to shock. It is preferably contraindicated in people with poor liver and kidney function.