How long the side effects of enhanced CT contrast can be eliminated is directly related to the time of contrast occurrence and the severity of contrast occurrence. If the side effects occur acutely within 1 hour, most of them can be eliminated within 1-2 days. The contrast agent metabolism time is usually within 24 hours, and most of the patients do not have underlying kidney disease, most of them do not have too much problem, and the time of patients with underlying kidney disease will be relatively longer. If patients experience chronic side effects, such as those occurring within 1 hour-7 days after contrast agent injection, the time to eliminate the side effects should be considered according to the severity, and more serious impairment of kidney function can last a lifetime. Patients need to drink a lot of water after contrast injection to promote metabolism and contrast excretion, and patients with underlying renal disease need to be hydrated.