When urinary frequency occurs after surgery, you need to know the specific site of the surgery and determine whether the frequency is related to the surgery. Possible causes: i. If a catheter is left in place during surgery, urinary frequency can occur for a short time after removal of the catheter. Because the urinary catheter irritates the mucosa, resulting in localized edema or increased sensitivity of the mucosa, the frequency of urination can be relieved 24 hours after removal of the catheter. Second, if after the surgery, the patient needs to fast and needs proper rehydration, the process of rehydration infusion may cause frequent urination, mostly related to the high amount of rehydration fluid. Third, if it is a surgery of urethra or bladder, it will produce frequent urination for a short time after the surgery. Waiting for the mucosa to recover and heal completely after the surgery, the frequent urination can disappear naturally after the surgery. Fourth, if it is bladder surgery, such as partial bladder removal, resulting in a reduction of the effective bladder capacity, frequent urination may occur after surgery, which will be informed in detail before surgery.