Before the birth of a small baby, the umbilical cord is the link between the fetus and the mother, undertaking the important functions of fetal oxygen supply and material metabolism transportation. However, after the baby is born, many parents have many doubts about the care of the baby’s umbilical cord. After the birth of a newborn, the umbilical cord, which is connected to the placenta, is ligated and cut off, and the stump of the umbilical cord eventually dries and falls off, leaving a small depression in the middle of the baby’s abdomen, the belly button. Although the navel is small, there are also diseases that can occur if it is not properly cared for. After the umbilical cord is ligated, be sure to keep the umbilicus clean and dry, clean the umbilicus with hydrogen peroxide or 75% alcohol, apply 1% to 2% purple drops, and then wrap it with sterile gauze. Umbilical flesh tooth swelling is the result of long-term untreated umbiliculitis, or the umbilicus is mistakenly stimulated by foreign objects such as talcum powder, umbilical cord powder and talcum powder. It should be cauterized with 10% silver nitrate or surgically removed at the hospital. Umbilical velvet is a proliferation of yolk duct remnants (embryonic remnants) in the umbilicus of a child, also known as umbilical yolk duct polyps or umbilical polyps. The umbilical polyp is a polyp-like growth that appears in the umbilicus of a child after the yolk duct has been occluded and the distal mucosa (intestinal mucosa) has not completely disappeared. The umbilical velvet has a slightly red appearance and is located in the center of the navel. It should be cauterized with 10% silver nitrate or surgically removed at the hospital. Umbilical ureteral fistula due to unclosed umbilical ducts is rare clinically and is characterized by leakage from the umbilical orifice, with local symptoms when complicated by infection. The diagnosis can be confirmed by injection of methylene blue into the bladder to observe for blue staining of the leaking fluid, injection of contrast into the fistula hole, excretory cystourethrography or cystography. Treatment is surgical removal of the fistula, and since some patients may have lower urinary tract obstruction, care should be taken to remove the obstruction. An umbilical hernia has a spherical or hemispherical, walnut-sized mass that disappears when the child is quiet or bedridden. It usually heals on its own, but if it does not heal at the age of 3, it should be repaired surgically. Umbilical bulge in the umbilical cord area has abdominal organs protruding outside the abdomen, and the exterior of the organs is only covered by a layer of peritoneum and amniotic membrane, and there is no skin on the surface. The bulging organ is clearly visible in the abdominal wall. If not treated in time, once the cystic membrane is ruptured and the internal organs are exposed, peritonitis and sepsis can be complicated. Therefore, once diagnosed, surgical repair should be performed as soon as possible.