After doing the enhanced CT examination, doctors suggest patients to drink as much water as possible, drinking for 3-4 days. Drinking more water than usual within 3-4 days after the examination can speed up the metabolism and help the contrast agent to be excreted from the body. Because enhanced CT requires injection of contrast agent, which is metabolized by the kidneys, if the patient’s kidney function is not good, the contrast agent may aggravate the damage to the kidney function, so patients with renal insufficiency need to do enhanced CT with caution. If patients have to do enhanced CT, they can choose contrast agents that are less harmful to kidney function and try to drink more water after the examination to help the contrast agent to be excreted from the body.