Green stool — when your feces look green — is usually the result of something you ate, such as spinach or dyes in some foods. Certain medicines or iron supplements also can cause green stool.

Newborns pass a dark green stool called meconium, and breastfed infants often produce yellow-green stools. In older children and adults, green stool is not common. However, it's rarely cause for concern.

Infants

Infants might have green stool as a result of:

• Not finishing breastfeeding entirely on one side. This can result in baby missing some of the high-fat-content breast milk, which affects the digestion of the milk.
• Protein hydrolysate formula, which is used for babies with milk or soy allergy.
• Lack of typical intestinal bacteria in breastfed infants.
• Diarrhea

Children and adults

Causes of green stool include:

• Diet high in green vegetables, such as spinach.
• Food dyes.
• Diarrhea
• Iron supplements.

Call a healthcare professional if you or your child has green stool for more than a few days. Green stool often happens with diarrhea, so drink plenty of fluids and seek immediate medical attention if you or your child becomes dehydrated.