What Causes Green Stool in Newborns?

New mothers can promptly assess their baby’s health by observing the baby’s stool daily. Stool color is typically closely related to diet and feeding practices. So, what causes green stool in newborns?

What Causes Green Stool in Newborns?

Green stool may occur when a newborn has a cold or digestive upset, often accompanied by spitting up. If the newborn is underfed, hunger may accelerate gastrointestinal motility, preventing adequate conversion of bilirubin in the intestines—resulting in loose, green stool. During fat digestion, insufficient bile utilization leads to excess bile being excreted in the stool, imparting a green hue. Additionally, iron-fortified formula may cause yellowish-green stool if the infant cannot fully absorb the iron.

If the stool is dark green, consider possible digestive dysfunction, gastrointestinal disease, or gastroenteritis. Under medical guidance, probiotics such as “Mami Ai” (a brand of pediatric probiotic) may be used to help improve symptoms. However, if the baby’s stool is green but the infant remains alert, feeds and sleeps well, gains weight appropriately, and exhibits no other concerning symptoms, close observation alone is usually sufficient—no specific intervention is required. If the mother remains concerned, she may consult a healthcare provider and have the baby’s stool tested.

Ensure proper abdominal warmth for the baby—cover the umbilical area with a towel during sleep to prevent chilling. We hope this information is helpful to you.