Why green baby poop is usually nothing to worry about

Noticed some green in your baby's diaper and wondering if it's normal? You're not alone! Though it might look odd, green poop can be totally fine and shows up for all sorts of reasons. Here's what might be causing your baby's Wicked-hued poop and when (if ever) to worry.

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), but it can be the result of something a little more concerning, like an infection.

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.

If you're curious about other baby poop colors, be sure to check out our complete guide to baby poop and take a look at our baby poop photos (if you're not squeamish).

Why does my newborn have green poop?

"Dark green is actually the right color for newborn poop," says Chandani DeZure, M.D., a pediatrician and member of the BabyCenter Medical Advisory Board.

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 a 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?

Green poop isn't unusual in babies, and – while it can signal a problem – it's usually not concerning, says Dr. DeZure. In fact, for some babies, green is a pretty normal poop color (because of their diet or a supplement they're taking, for example).

A studyOpens a new window of more than 1,000 healthy babies found that almost half had green poop for at least a week sometime during their first 4 months of life, whether they were breastfed or formula fed.

Here are some of the reasons your baby's poop may be green:

• 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 in sugar and low fat.) In this case, their poop may be bright green and frothy or foamy, and your baby may be gassy.
  "My first had green, frothy poop because I had an oversupply and he wasn't getting enough hindmilk," says BabyCenter Community member Acrazymamax3. "It resolved when I started nursing on only one side at a time."
• Infection. Your baby may have a viral or bacterial infection, like a cold or stomach flu. In this case, their poop may be bright green.
• Food allergy or intolerance. Your baby may have an allergy or intolerance to milk proteins in their formula or your breast milk. Once your baby starts eating solids, this 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. According to the American Academy of PediatricsOpens a new window (AAP), grape-flavored Pedialyte, green Jell-O, and green fruit snacks can cause green poop. So can pureed green foods, such as spinach, peas, and green beans. The poop can be bright green to greenish brown.
• Supplements and medications. Iron supplements, foods that are fortified with iron, and certain medications (taken by your baby or you, if you're breastfeeding) can turn a baby's poop dark green.
• Phototherapy. If your baby is being treated with phototherapy for jaundice, it may turn their poop greenish.

"My 6-week-old has been pooping green pretty much since birth," says BabyCenter Community member timg8. "It legit looks like pesto. Our pediatrician said this is normal and exclusively breastfed babies have a very wide range of 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.

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.

My 6-week-old has been pooping green pretty much since birth. It legit looks like pesto. 

- BabyCenter Community member timg8

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

Why is my toddler's poop green?

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

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 makes their poop green.

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, 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.

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