As a parent, you might find yourself paying more attention to your baby’s poo than you ever imagined! From mustard yellow to green and brown, baby poo can come in a surprising range of colours and textures.

Yellow, green and brown baby poos are generally normal, with colour and consistency often changing as your baby grows, their digestive system develops and their diet evolves. However, certain colours, including white, pale grey, red or black may require medical attention.

This baby poo colour guide is designed to take the guess work out of different poo colours, how stools differ between breastfed and formula-fed babies and when to seek advice from a healthcare professional.

What colour should baby poo be?

A baby’s stool can tell us a lot about their health, from whether they are receiving the right nutrition to whether their internal organs are functioning efficiently. The ideal colour for a baby’s poo depends on a few factors. Factors such as their age, their diet and any underlying medical conditions. A range of colours such as green (light, dark or frothy), yellow and brown are all considered normal and can occur at different stages of infancy.

What can different poo colours indicate?

Black in the first few days of life

Black coloured poo during the first few days of life can be a newborn’s first poo, known as the meconium. The meconium is usually passed within 24-48hrs after birth and contains contents the baby has ingested in utero. The colour and consistency of the meconium is often described as very dark green or black and sticky and thick like tar. If a newborn hasn’t passed meconium within the first 48hrs of life, it is necessary to seek advice from a healthcare professional.

Dark green

Dark green stools are generally normal for an infant and can occur in both breastfed and formula fed babies. For a baby that is breastfed, dark green stools often relate to bile pigments and indicate their milk is moving quickly through their digestive system. For a formula fed baby, dark green poo can relate to the iron fortification in infant formulas.

Light green or frothy

Light green or frothy stools in a breastfed baby often indicate that they’re receiving more foremilk than the fattier hindmilk or a high volume of breastmilk in one feed. In a baby who is formula fed, a frothy or light green poo can indicate a few different things. Formula may be moving through the digestive tract quicker than usual, iron in the formula may be influencing a light green colour or a food sensitivity could be indicated. It is worth keeping an eye on the frequency of your baby’s stools being light green or frothy and consult a healthcare professional with any questions.

Mustardy yellow

Mustard yellow stools in breastfed babies are described as loose and seedy and are common in newborns. Babies will often pass multiple loose stools a day for the first week of life. Mustardy yellow stools are less common in formula fed babies whose stools are more likely a browner colour and firmer texture.

Darker yellow or light brown

Very common and normal for formula fed babies as their stools are often darker and harder than breastfed babies due to the differing compositions between breastmilk and formula.

Darker browns

Common and very normal for babies are they get a little bit older, their digestive system develops and their diet evolves (Ie. Starting solids).

Colours to watch out for

White or light grey

An abnormal colour for young ones. White or light grey stools should trigger a visit to a trusted healthcare professional to rule out any potential issues with the liver.

Black after the first week of life

Black stools are completely normal if it is your baby’s first poo (this is known as the meconium which is described in more detail above). However, if your baby has already passed meconium and their stools continue to be black or become black again, it’s important to seek timely medical care. Black stools outside of meconium, can sometimes indicate internal bleeding.

Red

Stools that are red or contain red streaks are not considered normal and trusted healthcare practitioner advice should be sought after. Red stools can indicate a few things including, anal fissures (minor tears caused from baby straining to pass stools) or gastrointestinal irritation. On rare occasions, babies that are on solids can have reddish coloured stools from foods like beetroot.

Why is a newborn's poo often darker?

Newborns first poo is referred to as meconium and is passed between 24-48hrs after birth. Meconium is often described as black, sticky, thick and tar like. Meconium consists of all the contents your baby has ingested while in utero, such as water, amniotic fluid, cell debris and mucus. If your baby does not pass meconium within 48hrs after birth, it’s important you contact a healthcare professional for advice.

Does starting solids change my baby's poo?

Yes, starting solids often changes the colours and consistencies of baby’s poo as their digestive system is adapting to processing a different form of nutrients. The main changes include:

• Texture: Stools become harder and less liquid. With the occasional undigested piece of food being identifiable within the stool.
• Odour: Smell becomes stronger.
• Frequency: Some babies may poo less often after starting solids. 
• Colour: Poo often becomes a darker shade and more of a brown instead of yellow after starting solids. Certain pigmented foods can also influence the stool’s colour, such as spinach influencing green, carrots influencing orange or beetroot influencing red.

When should I be concerned about my baby's poo colour or consistency?

If your baby has white, red or black (outside of passing meconium) coloured stools, it warrants a call or visit to a trusted healthcare professional. In terms of consistency, if your baby is passing hard and dry pellet like pieces of stool, they’re most likely constipated. Constipation should trigger medical assessment if accompanied by symptoms such as, blood in the stool, bloating, pain when passing stools, fever or vomiting. If your baby has consistent diarrhoea accompanied by fever, vomiting or dehydration, medical assessment is also necessary. Lastly, if you notice any blood or mucus in your baby’s poo, it’s best to consult a trusted healthcare practitioner.

Common misconceptions about baby's poo

There are a few common misconceptions about a baby’s poo habits. The most common I have come across are:

Myth: Babies with green poo have an infection.

Fact: Green poo in infants is generally normal and does not indicate an infection. Dark green stools in a breastfed baby can indicate their milk is moving quickly through their digestive system. For a formula fed baby, dark green poo can relate to the iron fortification in infant formulas.

Myth: Grunting while pooing means my baby is constipated.

Fact: It is common for a baby to strain, grunt or even turn a little red faced while pooing. This happens as babies are learning how to coordinate the right muscles in their abdomen, pelvic floor and sphincter to expel a stool from their bowel.

Myth: If a baby has watery poo, it’s diarrhoea and they have gastro.

Fact: If a baby is breastfed, they’re naturally going to have watery, mustard yellow-coloured stools, this does not equate to diarrhoea. In order to know the difference, diarrhoea is more likely if a watery stool is accompanied by your baby being lethargic, having a fever and showing a disinterest in their normal feeding pattern. In this latter case, you should seek personalised advice from a healthcare professional.

FAQs

How often should my baby be pooing?

How often your baby should be pooing is very dependent on their age and whether they are formula-fed, breastfed or on solids. Newborns often poo several times a day after they’ve passed meconium (within the first 24-48hrs of life). As babies grow, their bowel movements often become less frequent, some exclusively breastfed babies (over six weeks old) may even go a few days without a bowel movement. Formula-fed babies often have more regular poos.

Is it normal for my baby's poo to change colour?

Yes, its definitely normal to notice your baby’s poo changing colour as they grow and their digestive system develops. Yellow, green and brown are all considered normal stool colours. Changes in feeding, digestion and the introduction of solids can all influence the colour. However, it’s important to note, if you notice white, grey, red or bloody or black stools (after meconium has passed), it’s important to seek advice from a trusted healthcare professional.

Can transitioning to formula change my baby's poo colour?

Yes, transitioning from breastmilk to formula or even formula to a different formula can affect the colour, consistency and frequency of a baby’s poo. 

While breastfed babies commonly produce mustard-yellow, loose stools, formula-fed babies often have slightly darker, thicker stools that range from yellow and tan to brown and green.

When transitioning to a new formula, it’s important to go slowly, see our transition guide here. These changes are generally normal as your baby’s digestive system adjusts to a different milk composition. If you notice persistent diarrhoea, hard or painful stools, blood in the stool or feeding difficulties, it’s important to seek professional advice.

How can I tell if my baby is constipated?

Constipation in babies is generally identified by the consistency of their poo and how difficult it is to pass, rather than how frequently they have a bowel movement.

Common signs of constipation in infants include hard, dry or pellet-like stools, discomfort when passing poo and a firm abdomen. It is also common for young babies to grunt, strain or turn red when passing a stool as they’re learning to coordinate muscles involved in pooing.

If your baby is regularly passing hard stools, appears uncomfortable or has a significant change in their usual bowel habits, speak with a healthcare professional.

When should I seek medical advice about my baby's poo?

Most changes in a baby’s poo can be normal however certain signs do require prompt medical attention. Please seek urgent medical advice if you notice:

• White, grey or chalk like stools 
• Black, thick, sticky stools after your baby has passed meconium
• Red or bloody stools
• Persistent watery diarrhoea
• Hard, painful stools or significant changes in frequency
• Poor feeding, signs of dehydration or poor weight gain.