When urination occurs and the navel hurts, it is necessary to go to the hospital for further examination to determine if there is a lesion of the umbilical ureter. In normal people, when the umbilical ureter degenerates after birth, the connection between the bladder and the umbilicus is severed and urine from the bladder does not enter the umbilicus through the umbilical ureter, resulting in pain around the umbilicus or an attack of umbiliculitis. However, in a few cases, the umbilical ureter does not degenerate and urine from the bladder enters the umbilical ureter, causing recurrent infections and diseases such as umbiliculitis or umbilical ureteral cysts, or umbilical ureteral fistula. The typical characteristics are urine leakage from the umbilicus during urination, redness, swelling and pain in the umbilicus, or a subumbilical mass. An ultrasound examination of the umbilical ureter or an abdominal CT examination is required to further clarify the presence of a lesion in the umbilical ureter. If the presence of umbilical ureteral lesions is confirmed, aggressive anti-infection treatment is needed, and umbilical ureterectomy is required after the inflammation has healed to completely cure the disease.