What Can Your Baby’s Poo Look Like?

You’ve probably already noticed that your baby’s poo can change quite a bit in both colour and texture. It can look different depending on whether your little one is having breastmilk, formula, a combination of both, or if you’ve already started weaning onto solid foods.

In this article we’ll walk through the most common baby poo types, what they tend to look like at different ages, and how often you might find something in the nappy.

Many first-time mums (and dads!) get a bit of a fright the first time they see green, mucus-like, lumpy or very runny poo. Sometimes it can even look almost black, or have a reddish tinge that makes you worry about blood.

If you feel something isn’t right, it’s always best to speak to your GP, health visitor or NHS 111. This guide is here to help you recognise the different types of baby poo you might see as your baby grows – but it doesn’t replace professional medical advice.

In the First Few Days: Meconium

During the first 1–4 days after birth, your baby passes a very distinctive poo called meconium. This is usually black or very dark green, thick and sticky, almost like tar. It’s made up of everything your baby swallowed in the womb – such as amniotic fluid and tiny skin cells – and it fills their bowels before birth. cambspborochildrenshealth.nhs.uk+1

To help clear this “newborn tar”, your baby needs the first milk, known as colostrum. This early breastmilk acts a bit like a gentle laxative and helps meconium move through the bowels more quickly. Getting meconium out matters, because if it hangs around too long it can contribute to jaundice.

That’s why it’s so important for your baby to start feeding as soon as possible after birth, and to continue with frequent, effective feeds in the following days, ideally offering both breasts so your baby gets enough milk.

An “intermediate” poo (transition stool) usually appears around days 2–4. It becomes more greenish or yellow-green, and the colour is still fairly dark because the breastmilk is now starting to colour the poo.

If your baby is still passing black meconium after day 5, get help from your midwife, health visitor or GP, as this may suggest your baby isn’t getting enough breastmilk. 

There can be a 24-hour gap between the last meconium and the first proper breastmilk poo. This is usually fine as long as your baby is:

• weeing regularly,
• feeding actively and effectively,
• and otherwise seems well.

Breastfed Baby Poo: What’s Normal?

From around day 5–6, once your milk has “come in”, a breastfed baby’s poo usually turns mustard-yellow, often with a creamy or slightly grainy texture. This is what most parents think of as typical breastfed poo.

As long as your baby is exclusively breastfed, this kind of yellow, soft, sometimes seedy poo is considered normal.

How often should a breastfed baby poo?

This can vary a lot from baby to baby:

• Some babies may poo 3–5 times a day,

• Others may only poo every 3–5 days, or even less often as they grow. derbyshirefamilyhealthservice.nhs.uk+1

If your baby:

• has plenty of wet nappies,
• is gaining weight well,
• seems content between feeds,

then having less frequent poo can simply mean they are using up more of the breastmilk, leaving less waste. That’s usually absolutely fine as long as the poo, when it does appear, is still soft and your baby doesn’t seem to be in pain.

Formula-fed poo is often thicker, darker and more paste-like, and these babies can sometimes poo less often than breastfed babies.

Green Poo: Is It a Problem?

Seeing green poo in the nappy can look alarming, but a bit of green now and then is usually nothing to worry about.

A slightly greenish poo once or twice a day can simply mean that breastmilk is moving through your baby’s gut a little more quickly, so the bile (which is naturally green) doesn’t break down completely to yellow.

Sometimes, if your baby is getting more of the milk from the start of the feed – which is naturally richer in lactose and a bit thinner – and less of the creamier, higher-fat milk that comes later, they may struggle to digest all the lactose. This can also lead to frothy or green poo. 

What can you try at the breast?

If you often notice greenish poo, and your baby is otherwise well, you can try:

• Offering mostly one breast per feed, so your baby can get more of the higher-fat milk at the end of the feed.

• Avoid swapping breasts too quickly just because your baby pauses – give them time to settle back into the same side.

If green poo only appears occasionally, there’s usually no need to overthink it. Remember, colour alone doesn’t always signal a problem.

When to be more cautious with green poo

Get advice from your GP, health visitor or NHS 111 if:

• your baby has frequent, very watery green poo over a longer period,

• there are other signs of being unwell (fever, poor feeding, unusual sleepiness, very unsettled),

• or you’re worried about a possible gut infection.

If you regularly pump after every feed, there’s a chance your baby might mainly be getting the more lactose-rich milk, while a lot of the creamier milk ends up in the bottle or storage container. This can lead to persistent green poo in some babies.

You might consider:

• gradually reducing the amount of pumping, or

• re-timing pumping so your baby feeds directly from the breast when the milk is a bit creamier.

Always make any changes gently, and if you’re unsure, talk to your midwife, health visitor or an IBCLC lactation consultant.

Mucus in Your Baby’s Poo

A slimy or mucus-like poo can be completely normal from time to time.

Your baby may swallow saliva or nasal mucus (especially when they’re a bit snuffly), which can irritate the gut slightly and lead to mucus in the nappy. This is particularly common during teething, when babies drool much more.

Unfortunately, this can also irritate the nappy area, causing redness or nappy rash in some sensitive little ones.

If you notice that mucus in the poo carries on for several days or is combined with other worrying symptoms (like blood, fever, poor feeding or weight gain issues), get in touch with your GP or health visitor.

Black Poo Outside the Newborn Period

As we mentioned, black or very dark green meconium is normal in the first few days of life. After day 4–5, your baby’s poo should start to change from black to greenish, then to yellow once meconium has cleared and feeding is established.

If you see black poo later on, it may mean:

• your baby isn’t getting enough milk, or

• there might be another issue that needs medical advice

Sometimes, if a baby is given iron supplements (always under medical guidance), this can also turn the poo very dark or almost black, and might also cause constipation.

Very occasionally, dark blackish stool may suggest the presence of digested blood. This is why it’s important to speak to a health professional if black poo appears after the newborn phase.

Blood in the poo may also come from cracked or bleeding nipples during breastfeeding. A baby can swallow small amounts of blood without you realising, and this can then show up in the nappy.

If you suspect the blood might be coming from your own nipples, it’s worth seeing a breastfeeding specialist, midwife or health visitor to help with positioning, latch and nipple healing.

If you think the blood may be coming from your baby’s own body, contact your GP, health visitor or NHS 111 for advice urgently.

The Scariest One: Blood in the Nappy

Finding what looks like blood in your baby’s poo can be very frightening. The good news is that not all red or pink stains are actually blood, and even when they are, it doesn’t always mean something serious is wrong – but it should always be checked.

What can cause red or blood-streaked poo?

• If your nipples are sore, cracked or bleeding, your baby can swallow a small amount of blood while breastfeeding. This tends to make the poo look darker, sometimes almost black, rather than bright red. It usually doesn’t harm your baby, but it’s a strong sign that you need nipple care and breastfeeding support.
• A tiny tear around the bottom (anal fissure):
  If your baby is a bit constipated, or passes a particularly hard stool, there can be a tiny tear around the anus, which can cause bright red streaks of blood on the outside of the poo or on the wipe.
• Possible cow’s milk protein allergy or sensitivity:
  In some babies, a reaction to cow’s milk protein (either from formula or from dairy in mum’s diet if breastfeeding) can irritate the gut and cause mucus and blood in the poo.
• Red fibres or food:
  Babies are experts at putting everything in their mouths. They can swallow red fluff, paper or tiny threads, which may then appear in the nappy and look alarming. Once your little one is weaning, red-coloured foods (like beetroot or certain fruit purées) can also make the poo look reddish.

If you see bright red, fresh blood in the poo, or blood combined with diarrhoea, fever or a very unwell baby, seek help urgently from your GP, NHS 111 or A&E if you’re really worried.

“Cottage Cheese” or Lumpy Poo

Sometimes your baby’s poo looks as if it’s full of little white or yellowish lumps, a bit like cottage cheese or curds, especially in breastfed babies.

Don’t panic – this often just shows that:

• the digestive system is still maturing, and

• some parts of the breastmilk are not fully broken down yet.

As long as your baby is happy, feeding well and gaining weight, lumpy or “curdy” poo is usually completely normal. 

Very Watery Poo: Is It Diarrhoea? 

In the first weeks, babies can poo several times a day, sometimes after almost every feed. For a breastfed baby, poo can range from creamy and soft to quite runny, and that’s still considered normal.

True diarrhoea is more about a sudden change – for example:

• poo becomes much more watery than usual,

• nappies are being filled far more often than before,

• poo may have a stronger, unpleasant smell,

• your baby might seem unwell, have a fever, or refuse feeds. 

If you notice a clear change like this, especially if your baby is very small, speak to your GP, health visitor or NHS 111 straight away. Babies can become dehydrated quickly.

Constipation in Babies

Even little babies can struggle with constipation. This usually means:

• the poo is hard, dry or pellet-like,
• it seems to hurt when they try to go,
• they may only pass small amounts of poo, several times a day,
• a baby may cry, go red in the face, arch their back or pull their legs up when trying to poo,
• an older toddler may hide in a corner, behind the sofa, or under the bed when they feel the urge, and may try to hold the poo in.

Poo-holding can also appear:

• when a child is starting potty or toilet training,
• when they’re starting nursery or childcare,
• or if they don’t feel comfortable using the toilet or potty away from home.

Constipation can also show up around weaning, when new foods are introduced.

If you suspect constipation, speak to your GP or health visitor. They can help you with:

• advice on fluids and diet (for older babies),
• whether any medication or treatment is needed,
• and how to break the cycle of painful poo and withholding.

When Should You See a Doctor?

Always take note of what the poo looks like, as well as how often it appears. A quick photo on your phone can be really helpful for your GP, health visitor or midwife, and you can even bring the nappy with you (in a sealed bag!) to your appointment.

Get same-day advice from your GP, health visitor or NHS 111 if:

• your baby’s poo suddenly looks very different from usual,

• there is blood, large amounts of mucus, or black poo (after the first few days),

• your baby has possible diarrhoea, especially with fever or vomiting,

• your baby seems very sleepy, unusually irritable, or refuses feeds,

• or you have a gut feeling that something simply isn’t right.

Most of the time, even strange-looking poo doesn’t mean a serious problem – but it’s always better to check with a professional if you’re unsure.

Sources:
NHS – Baby poo in nappies
NCT – Newborn baby poo: what to expect