Indwelling urinary catheters are mainly used clinically for patients who have urinary retention and cannot urinate on their own, or for the treatment of certain diseases, which often require indwelling urinary catheters. Infections can easily occur after a urinary catheter is left in place. Measures to prevent infection mainly include: i. If the patient is able to drink, encourage the patient to drink more water and produce more urine so that urine can flush the urinary catheter and reduce the chance of infection. If they cannot drink water, increase the amount of fluid infusion appropriately. Second, keep the urethra clean, especially in and around the external urethral opening, which can be cleaned with iodophor 1-2 times a day. Third, change the urinary catheter regularly, you can change it once every two weeks and change the urine bag once a week, the bag should not hang too high, it should be below the bladder level.