What causes a baby to have black stools?

Black stool generally refers to dark-colored bowel movements. This may be caused by excessive iron intake from food, such as when a baby takes iron supplements, which can lead to black stools. It could also result from the baby consuming foods made from animal blood. If indigestion occurs, bile released into the intestines may not be properly digested and absorbed, causing green stools; in severe cases, this might even lead to black stools. Black stool in babies cannot rule out the possibility of gastrointestinal bleeding.