Why Is My Kid's Poop Green?

Medically reviewed by Karen Gill, MD, FAAP on August 16, 2016Written by Jessica Timmons on August 16, 2016
green poop in kids

As a parent, it’s normal to take note of your child’s bowel movements. Changes to texture, quantity, and color can be a useful way to monitor your child’s health and nutrition. But it can still be a shock if you discover green poop as you change your baby’s diaper or help your toddler in the bathroom.

Here’s the scoop on green poop, what may cause it, and when you should call your doctor.

Green poop in infants

It’s rare to be a parent who doesn’t change at least one greenish, poopy diaper. When babies are just a few days old, their poop is changing from the thick black meconium that they were born with (which can have a greenish tint) to a mustard-like substance. During this transition, your baby’s poop may look a little green.

As your baby gets older, their diet will have a direct impact on the color and texture of their bowel movements. Babies fed an iron-fortified formula or given an iron supplement may pass dark, green poop. It’s also normal to see poop that ranges from a yellowish-brown to light brown. If you’re exclusively breast-feeding, your baby’s yellow poop comes from the fat in your milk.

Causes of green poop in infants

The occasional green poop in your breast-fed baby’s diaper could have a few causes. These include the following.

What you’re eating

If you’re snacking on lots of green vegetables or foods with green food coloring like sodas and sports drinks, this can change the color of both your breast milk and your baby’s poop.

Your baby is ill

If your baby has a stomach bug or virus, it can have an impact on the color and consistency of their poop, especially if they also have diarrhea. This can occur in formula-fed babies, too.

Baby’s sensitive or allergic to something in your diet

Your baby’s poop could become green or have a mucus-like consistency because of sensitivity to something in your diet, though this is uncommon. They might also be sensitive to a drug you’re taking. In these cases, the green stool with mucus is usually accompanied by other symptoms like tummy problems, skin, or breathing issues. This can also happen to older babies as new foods are introduced. 

Foremilk/hindmilk imbalance or oversupply

If you have a forceful letdown reflex, or an oversupply of breast milk, your baby may be getting more foremilk than hindmilk. Foremilk is the thinner milk that comes at the beginning of a feeding. It’s sometimes lower in fat and higher in lactose than the creamier milk that comes toward the end of a feeding. This is known as hindmilk.

If your baby fills up on the foremilk because your milk production is too high, it is theorized that lactose may not be properly balanced with fat. Then your baby might digest it very quickly, which could lead to green, watery, or frothy poop.

Some people feel that the overabundance of lactose may also cause gassiness and discomfort for your baby. This might be the case if you switch your baby to the other breast before fully draining the first breast as well.

This kind of green stool isn’t typically a problem if your baby is happy, healthy, and gaining weight normally. Allowing your baby to nurse on one side long enough to get the higher fat milk is usually enough to solve the issue.

What your baby eats

As your baby gets bigger and begins eating solid foods, green poop may strike again. Introducing foods like pureed beans, peas, and spinach can turn your baby’s poop green.

Mucus

Slimy green streaks that seem to glisten in your baby’s poop indicate the presence of mucus. It’s thought that this sometimes happens when your baby is teething and drooling excessively. It can also be a sign of infection. Talk to your pediatrician if it doesn’t go away and is accompanied by other symptoms of illness.

Green poop in toddlers and older children

If you notice that your child’s poop is green, it’s probably because of something they ate. Medications and iron supplements can also be the culprit. While it’s not very common, it’s usually not cause for concern.

In children and even adults, green poop can be caused by:

  • natural or artificial colors found in foods like spinach
  • diarrhea caused by food or illness
  • iron supplements

The takeaway

In many cases, a child’s green poop is accompanied by diarrhea. If that’s the case, make sure they’re getting lots of liquids to avoid dehydration. If your child’s diarrhea and green poop doesn’t go away after a few days, speak to your pediatrician. 

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