Why Does My Baby Have Green Stool?

Green stool in infants is commonly caused by indigestion or acute gastroenteritis. One possible cause is food coloring: some infants consume green-colored foods—or foods rich in iron, such as animal liver or blood—which may result in stools appearing dark green or blackish-green. This condition typically requires no specific medical treatment; dietary adjustment alone is usually sufficient.

A second cause is indigestion. When infants experience poor digestion after eating, nutrient absorption may be impaired. In such cases, stools may appear green and may be accompanied by symptoms such as frequent loose stools (diarrhea), abdominal pain, or bloating—classic signs of indigestion.

A third potential cause is intestinal inflammation. Inflammatory conditions of the gut can lead to pathological diarrhea, significantly impairing digestion and absorption. As a result, stool color may turn green. Additionally, certain hepatobiliary disorders—such as those affecting bile pigment metabolism—may increase bilirubin excretion, leading to greenish, dark, or yellowish discoloration of the stool. If parents are uncertain about the underlying cause, they should promptly take their child to a hospital for evaluation by a pediatrician.