Why your baby's poop is green

Green is actually a normal color for baby poop – though in some cases it can indicate a viral or bacterial infection, or a food allergy or intolerance. Your newborn's first poop will be very dark green and look almost black. Over a few days, it'll turn to a lighter green, then yellow (if your baby's breastfed) or yellow/brown (if your baby's formula-fed). While green poop is usually no cause for worry, call the doctor if your baby has green poop and is also ill, or if you're concerned that something is wrong.

Mom changing baby's diaper
Photo credit: Nathan Haniger for BabyCenter

What is green baby poop?

While green isn't the number one poop color (that would be brown or tan), it's one of many common variations.

Still, it can be a little startling to see light green, dark green, or even bright green poop in your baby's diaper. Green poop usually happens without any significant cause (maybe your toddler had spinach that day, or maybe your baby is taking an iron supplement), or it can be the result of something a little more concerning, like an infection.

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Because stomach bile (the fluid in the gallbladder that digests food) is what makes poop brown, green poop usually means that the poop moved through the intestines quickly, without much chance for the bile to turn it brown. That's why diarrhea – which travels more quickly through your baby's intestines than regular poop – is often green rather than brownish.

Learn about the wide variation in baby poop colors and consistencies.

Why does my newborn have green poop?

Dark green is actually the right color for newborn poop!

Meconium – your baby's first poop – is very dark green, looking almost black. It's made up of amniotic fluid, skin cells, lanugo (the fine hair that covered your baby's body), and mucus. It's sticky, with a consistency like tar. It's very hard to clean up, but it has no odor.

Your baby will poop meconium within the first 24 hours of birth. As they begin drinking breast milk or formula, their poop will transition from this dark greenish-black color to a lighter color. It may be greenish brown, then greenish yellow, and finally yellow (or a yellowish brown). The consistency will change, too, from sticky to soft.

Why is my baby's poop green?

Your baby's poop may be green for any number of reasons, such as:

  • Not getting enough hindmilk when breastfeeding. Hindmilk is the high-fat, high-calorie milk your baby gets when they empty your breast. (The milk they get early in a breastfeeding session is foremilk, which is high-sugar and low fat.) In this case, their poop may be bright green and frothy or foamy, and your baby may be gassy.
  • Infection. Your baby may have a viral or bacterial infection, like a cold or stomach flu. In this case, the poop may be bright green.
  • Food allergy or intolerance. Your baby may have an allergy or intolerance to milk proteins, for example – in their formula or in breast milk, if you've eaten dairy. Once your baby starts eating solids, it can be a reaction to something they've eaten. If your baby has an allergy, you may also see streaks of blood in their poop. If they have a food intolerance, they may be gassy and unusually fussy. In either case, their green poop may also be frothy, and they may be gassy and spitting up.
  • Green foods. Once your baby is eating solids, anything that's green in their diet can turn their poop green ­­– often dark green. This includes pureed foods, such as spinach, peas, and green beans.
  • Supplements and medications. Iron supplements and certain medications (taken by your baby or you, if you're breastfeeding) can turn a baby's poop dark green. There's no need to change the supplement or medication unless it's causing problems.
  • Phototherapy. If your baby is being treated with phototherapy for jaundice, it may turn their poop greenish.
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Take a look at our baby poop photos (if you're not squeamish) to see what's normal.

Are breastfed babies more likely to have green poop?  

Actually, green poop is common in both breastfed and formula-fed babies, but it's more common in formula-fed babies. 

While breastfed babies tend to have poop that's yellowish (and sometimes slightly greenish), formula-fed babies have poop that's more brown: usually tan, yellow/brown, or green/brown. Formula-fed babies also tend to have smellier poop, because breast milk is digested more quickly than formula.

Keep in mind that a change in your baby's diet – switching formula, changing what you eat if you're breastfeeding, or introducing solids – can result in a change in your baby's poop.

Learn more about what formula-fed babies' poop looks like.

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Why is my toddler's poop green?

Your toddler's poop may be green for many of the same reasons that a baby's poop might be green, including a viral or bacterial infection, food allergy or intolerance, or supplements or medications.

The most likely reason is the simplest, though. Because your toddler is probably eating a variety of foods now, they're more likely to come across a food or beverage that's green and in turn makes their poop green.

Your toddler may also be more exposed to other children (in daycare, for example) and so more likely to get a stomach virus and upset tummy and/or diarrhea, resulting in green poop.

Should I call the doctor about green baby poop?

Green poop is usually no cause for concern, unless your baby is also ill. Still, if you think something may be wrong – your baby's poop is really unusual for them and you can't see a reason for it, for example – go ahead and call.

Also call the doctor if your baby has green poop and other symptoms, such as fever, vomiting, and/or diarrhea. You'll want to be sure that your baby doesn't become dehydrated, especially if the illness continues for several days.

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Some poop colors are more concerning than green. Contact your child's doctor if your little one has red or black poop (which can indicate blood in their poop and gastrointestinal bleeding). And get medical care right away if your child has white or chalky gray poop. This can mean that your baby isn't getting nutrients because of an infection or serious liver problem.

Learn more:

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Karen Miles
Karen Miles is a writer and an expert on pregnancy and parenting who has contributed to BabyCenter for more than 20 years. She's passionate about bringing up-to-date, useful information to parents so they can make good decisions for their families. Her favorite gig of all is being "Mama Karen" to four grown children and "Nana" to nine grandkids.