What does a breastfed baby’s poo look like?

How does poo change in the first days?

A baby’s first poo is dark green-black, sticky meconium. As milk intake increases, it changes to transitional greenish-brown poo and then usually to loose yellow milk poo. This change typically becomes clear during the first days of life.

If poo is still consistently dark, sticky, and meconium-like around day five, especially with few wet nappies or ineffective feeding, milk transfer should be assessed. This does not mean every dark-green nappy is abnormal.

What colour and texture are common?

A typical breastfed baby’s poo is yellow or mustard-coloured, loose, and may contain small seed-like curds. Different shades of green can also occur. Curds alone do not mean the milk is undigested, and green alone does not show that milk is insufficient.

Disposable nappies absorb liquid, so small curds may remain on the surface with a wet ring around them. It may look unusual compared with an older child’s stool, but can be normal for a breastfed baby.

How can you tell loose poo from diarrhoea?

Breastfed baby poo is naturally loose, so one watery nappy does not automatically mean diarrhoea. A more meaningful change is a sudden increase from your baby’s usual pattern, with stools becoming much more frequent and entirely watery.

Seek advice if this comes with fever, vomiting, reduced feeding, unusual sleepiness, blood, lots of mucus, or fewer wet nappies. Dehydration can become important quickly in a young baby.

Why does poo frequency change over the weeks?

During the first weeks, some babies poo after every feed. At this age, stool frequency can help assess milk intake; very infrequent poo together with fewer wet nappies or weight concerns should not be dismissed as individual variation.

From around 3–6 weeks, some thriving exclusively breastfed babies may go several days, sometimes about a week, between poos. If the stool is soft and the baby feeds and grows well, this alone is not constipation.

How much can a photo tell you?

A photo can show colour and visible texture, but it cannot diagnose a problem. Lighting, the camera’s white balance, and the absorbent nappy surface can make yellow look orange, dark green look black, or pale yellow look lighter.

If you are unsure, check again in daylight against a white background. But if the stool may be white, red, or tarry black, do not rely on taking another photo; seek professional advice.

Which colours need more attention?

White, very pale grey, or clay-coloured stool may signal an important problem with bile flow. Red may be blood. After the meconium period, tar-like black stool is not considered a normal colour variation.

You cannot determine the cause of these colours at home from a photo. Especially for a newborn, if you see blood, white stool, or true black stool, save the nappy image or sample and contact a health professional.

What can you do today?

Instead of labelling one nappy, briefly record the colour, texture, and frequency of the last few stools.

Consider the appearance together with feeding, swallowing, wet nappies, and your baby’s general state when awake.

If you suspect white, bloody, or tarry black stool, check it in daylight but do not make seeking help depend on the photo.