Hello.Green mucus in stool is a sign of an infection. This is more common in young children . In most cases, the only sign of infection is the mucus in the stool and it shows malabsorption
in the intestines. Usually this should be self limiting as external factors like any change in diet etc have to be ruled out,however if this still persists after a day or two, you should take your child to your physician for a full checkup.Regards.