Patients do not necessarily need to drink more water after a CT exam. Whether or not to drink more water depends on the type of CT exam the patient has had. If the patient only had a CT scan of the organs, he or she does not need to drink more water after the test, and can live and eat normally. If the patient is doing enhanced CT examination, he needs to drink more water after the examination, because during the examination, the contrast agent needs to be injected into the patient through the vein, and most of the contrast agent is metabolized by the kidneys, which will have a certain effect on the kidneys, so drinking more water is to promote the rapid excretion of the contrast agent and minimize the effect of the contrast agent on the kidneys. Especially some patients with underlying kidney disease or elderly patients are more prone to nephropathy of contrast agents, patients should drink more water after the examination.