Why Do Breastfed Babies Have Green Poop

Why Do Breastfed Babies Have Green Poop

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Poo is something parents will have to deal with constantly from day 1 until they’ve finished potty training. You can tell a lot about a baby’s general health from the colour of the poo and its consistency and since you deal with so often it become a cause for concern if it’s different to the usual or what you expected.

Formula fed and breastfed babies do have completely different poos in their nappies, the biggest difference is the smell and colour. This article specifically looks at breastfed baby poo and what causes it to be green.

What is the normal colour for poo from a breastfed baby


Breastfed baby poop after the meconium phase in the first few days should be yellow/dark yellow/light green in colour. Generally, it looks a lot like a korma curry or mustard. It can vary day to day in its lightness and darkness but not significantly. It can sometimes have a greenish hue but not so much that you would actually say ‘it’s green in colour’.

Yellow poo means that the milk moved through the digestive system quickly as it should. Breastmilk does move relatively quickly because it is easy to digest and nutrient dense making easy work for their stomach and producing little waste and bad smells.

Darkening of the poo means it’s spent a bit more time in the bowels which will happen when the weaning phase begins or they switch to formula for some reason.

So, if your baby has yellow poop then it means they’re feeding well and not suffering from any kind of illness.

Why does my breastfed baby have green poo?

Green poop is common and usually means nothing at all, especially when it’s a light green olive colour, almost brown sometimes. Green poo doesn’t indicate anything in most cases unless it’s dark green. Here are some common causes which can darken the poop turning it green in a breastfeeding baby.

Formula milk

Adding formula into the mix can darken the poop and turn it greener/browner. Formula milk needs a little bit more time to digest over breast milk which is what causes this colour change. If this is the cases then green stools are nothing to be concerned about – if your baby is gaining weight and behaving normally then there’s nothing to worry about.

Read our recommendations on the best formula for breastfed babies.

Mucus from a cold

Possibly the most common cause of your baby poo turning green is as a result of a cold or a bug going around. The changing of the colour is caused by the bile they create in the GI and that they swallow from their stuffed noses. Generally, this won’t result in dark green poo but it can certainly darken it and added a green tinge. The change of colour will come and go with the cold itself.

In extreme cases, the saliva ingested from overuse of a dummy can cause some greening, but not much.

Read – Dummies for breastfed babies

This is the same for a breastfed baby’s and formula fed baby’s poop, however babies on powder milk will already have greenish poo to begin with so they may not notice.

It’s important to breastfeed them as much they want during a cold as it’s proven to give them comfort and help them get over the illness quicker.


Vaccinations are vitally important for health and not getting them can place your baby at a huge health risk. But, they can cause a bit of discomfort the day after and are common causes of a changes in their poos, from diarrhoea, explosive diarrhoea and you guessed it – green poo. Most vaccines can do this but the most common culprit is the rotavirus vaccine.

After getting the vaccine your health visitor will probably warn you about the incoming grumpiness and perhaps the incoming green poops. There’s nothing to worry about and they’re usually back to their best after around 48 house.

However, it’s worth mentioning to expect a lot of feeding afterwards for both the nutrition and comfort; there’s nothing better to help your child through this period than the boob.

Hindmilk imbalance

Hindmilk is the name for the milk at the end of the feed, hind milk typically has more fat content than fore milk (the milk that comes out first) which takes longer to go through the stomach and colon and you guessed it, turns more green as a result of this. Most healthy feeding babies will be getting enough of both fore and hind milk but a baby may get more than usual if they’re feeding more, here are some possible causes of cluster feeding;

  • Baby is getting a cold and needs extra comfort
  • When the child’s going through a growth spurt
  • When a baby’s had their injections

There are plenty of reasons why a baby may cluster feed (nipple cream can help here) and getting more hind milk than usual and it can turn poop green. If you’re concerned about more feeding than usual where it’s causing problems then seek a lactation consultant.

Cow’s milk intolerance

If your baby has recently been introduced to cow’s milk either in a drink, in a dairy product or via formula and their bowel movements and colour has changed significantly then it could be an intolerance to cow’s milk, which is more common than you think.

However, green poop is not the most obvious change if this is the case – they’ll likely be in some discomfort and visible pain, too. If you feel this is the case then seek medical advice when you can and cut out the milk until then and it should go back to normal.

Cow’s milk in the mother’s diet can cause some issues but on a smaller scale so it’s worth checking your intake if your little one seems to be struggling with their stools.

Eating green foods

A normal breastfeeding child who has started weaning with green vegetables and other green foods can end up with bowel movements which have taken a greenish turn. This is normal and quite common and can happen with foods of any colour not just green foods. Specifically, vegetables with chlorophyll (the stuff that makes them green in the first place) are the biggest contributor that cause green baby poop.

Read – Bab’s loving the veggies? Invest in a good blender to make it easier.

Is green baby’s poop a concern?

Poop may change colour from time to time and in the majority of cases there’s nothing at all to worry about. Some kind of a cold or bug is the most common cause, followed by their jabs and then an increase in consumption of hind milk.

But, a mother has a strong gut feeling and if you’re genuinely concerned then speak with a doctor for medical advice and a lactation consultant for anything related to breastfeeding including the latch. Your baby’s health is paramount so it’s never worth taking chances.


Every breastfeeding mother will encounter a baby’s poop turning green on several occasions and the above causes are most common. If the poo is different (colour or diarrhea) but there isn’t a sign of discomfort and they’re clearly gaining weight then you shouldn’t worry.

As is usual, if you have concerns and want definitive possible causes then seek medical advice from your doctor or health visitor and speak with a lactation consultant if you’re having any issues with the feeding and they may indicate a poor latch.