A baby’s belly button is the place where the umbilical cord enters and exits, and is actually a place where blood vessels enter and exit between the fetus and the mother during fetal life. It loses its function after the birth of the fetus, so it usually needs to be ligated and fall off on its own. Under normal circumstances, it will fall off 1-2 weeks after birth. If it does not fall off, there may be problems: first, the ligature is not too tight, too loose resulting in the normal fall off; second, the location of the ligature may not be suitable to cause a delay in the fall off time. Once there is a delay in shedding, you must pay attention to avoid infection, pay attention to disinfection, and if necessary, find a doctor to redo a ligature, ligature more tightly may be able to normal shedding in time. The main way to avoid infection is regular disinfection. We now generally use iodophor for disinfection, which is non-irritating, non-painful and more effective. In addition, some patients with umbilical lesions, such as umbilical velvet and umbilical sinus, may have delayed healing time and detachment time, so they need to see a surgeon for related treatment.