Generally speaking, the causes of yellowing inside the belly button of newborns include the following, firstly, it is caused by normal secretion, because after the newborn has just broken the umbilical cord, the local stump needs a process to heal. In the healing process, the child’s local stump will appear inflammatory exudation, thus manifesting as yellow. The second is caused by neonatal umbilitis, which can also cause yellowing inside the belly button, and often exude more, or even pus. The newborn will often cry and fuss at this time, which requires the timely application of iodophor and alcohol to disinfect the newborn.