When a catheter is inserted, the urethral mucosa will be stimulated by the urethral mucosa and cause local mucosal pain reaction, so pain will occur during the process of catheter insertion, especially when the patient is not cooperating well, such as after excessive tension or slight pain, the urethral mucosa or the sphincter of the urethra contract violently, which causes the urethral mucosa to tightly wrap the urethra. In order to overcome the resistance of the mucosa during the catheter insertion, the pain level will also increase, especially for men with prostatic hyperplasia, who have different degrees of urethral stricture, so the urethral tube will produce a slight pain or severe pain when passing through the stricture section. For some patients with external urethral strictures, encopresis or urinary tract infections, there is also significant pain during catheter insertion, which is caused by the irritation of the local mucosa by the catheter. Usually, after wearing a catheter, it is necessary to prevent infection, drink more water appropriately, and there is a gradual adaptation process after wearing a catheter, and there will be foreign body sensation and mild pain in the urethra in the short term.