Yellow mucus from the umbilical cord of a newborn may be pus. It may be due to umbilical infection, umbilical granuloma, umbilical sinus and other diseases. 1. Umbilical infection: due to the usual not pay attention to the newborn’s umbilical cord hygiene, umbilical cord disinfection is not complete, there may be secondary bacterial infections, manifested in the umbilical cord at the red, yellowish ooze, infection symptoms may also appear in the umbilical cord nest pus outflow phenomenon, the surface looks like the umbilical cord at the yellow mucous matter. 2. Umbilical granuloma: for newborns in the umbilical cord after the umbilical cord, the umbilical stump wound by foreign body stimulation, friction and the formation of granuloma, but also manifested in the umbilical cord has a small bright red swelling, there can be bloody or pus secretion oozing, and for the existence of secondary infection, there will also be umbilical cord with a yellow mucus phenomenon. 3. Umbilical sinus: mostly due to the yolk tube is not closed, it is easy to combine with the infection, the umbilical cord with yellow mucus phenomenon. Therefore, when a newborn baby has yellow mucus at the umbilicus, it is recommended to go to the hospital in a timely manner to clarify the cause of the disease, and then treat the cause of the disease.