Baby poop colours: what is normal and what needs checking

Newborn · Health · Reviewed 20 June 2026 · All articles

Checking your baby's nappy is one of those parenting rituals nobody quite prepares you for. The contents can change dramatically from day to day in the newborn period, and every change seems designed to prompt a late-night internet search. The reassuring truth is that baby poop comes in a surprisingly wide spectrum of colours, most of which are completely normal. But a small number of colours are genuine warning signs that need medical attention promptly. This guide walks through each colour, what it typically means, and when you should pick up the phone.

Quick colour reference

Meconium: the first nappies

The very first stools your baby passes are called meconium. Meconium is dark green to almost black in colour, with a thick, sticky, tar-like consistency that can be quite surprising the first time you encounter it. It is not actually made from digested milk at all. Instead, it consists of material the baby swallowed while in the womb: amniotic fluid, mucus, skin cells, and other substances ingested during fetal development.

Meconium stool is normal and expected. Most babies pass their first meconium within 24 to 48 hours of birth. If a baby has not passed any stool within 48 hours, the midwifery or paediatric team will investigate, as this can occasionally indicate a blockage. Once meconium is passed and milk feeds establish, the bowel begins to transition to normal milk-fed stool. The NHS notes that passing meconium is an important sign that the baby's bowels are working correctly.

Transitional stool: days three to five

Between days three and five, as colostrum gives way to mature breast milk and formula feeds become established, the stool enters a transitional phase. It changes from the dark tar of meconium to a brownish-green or even greenish-yellow colour. The consistency becomes softer and less sticky than meconium.

This transition is closely linked to the arrival of mature milk. If a breastfeeding parent's milk is delayed, or if a baby is not feeding frequently enough in the early days, the transition may take longer. A baby who is passing plenty of transitional stools by day four or five is generally feeding well. Midwives often count dirty nappies as a key indicator of adequate milk intake in the first week of life.

Breastfed stool: yellow and mustardy

Once breastfeeding is fully established, typically from the end of the first week onwards, breastfed baby stool takes on a very distinctive appearance. It is usually yellow, mustard yellow, or sometimes even a bright orange-yellow. The consistency is loose and seedy or curd-like, with small yellowish curds scattered through a more liquid base. It often has a mild, slightly sweet smell that parents describe as yeasty or even not unpleasant compared to adult stool.

This appearance can look alarming to a parent seeing it for the first time. It may look like diarrhoea. But for a breastfed baby, this loose, seedy, yellow stool is entirely normal. Breast milk is so efficiently digested that there is relatively little solid waste. The stools of an exclusively breastfed baby are rarely firm.

Frequency varies enormously between breastfed babies. Some will soil a nappy after almost every feed. Others, especially from around six weeks of age, may go several days between dirty nappies. Both patterns can be normal for breastfed babies, as long as the baby is feeding well, gaining weight, and the stool is soft when it comes. The absence of dirty nappies can be more concerning in a younger baby, so speak to a health visitor if you are unsure.

Formula-fed stool: tan, yellow, or brown

Formula-fed babies produce stool that looks quite different from the stool of a breastfed baby. Formula stool tends to be tan, yellow-brown, or light brown in colour. It is firmer in consistency than breastfed stool, more like peanut butter in texture, and has a stronger, more recognisable smell.

The colour can vary depending on the formula brand. Some formulas, particularly those with added iron, produce darker stool. This is not a cause for concern. Formula-fed babies tend to poop less frequently than breastfed babies, typically once or twice a day, though every baby is different. Hard, pellet-like stools, or straining with minimal output, may indicate constipation, which is more common in formula-fed babies. Speak to a health visitor or GP if you are concerned about constipation, as they can advise on dietary adjustments or treatment.

Green stool: usually normal, sometimes worth noting

Green stool in a baby prompts more questions than almost any other nappy content. The reassuring message is that green poop is common and often entirely normal. Here are the main reasons it occurs.

Normal variation

Some babies simply have green poop from time to time with no identifiable cause. As long as the baby is well, feeding properly, and gaining weight, occasional green stools need no action.

Foremilk and hindmilk imbalance

In breastfed babies, persistent frothy or bright green stools, sometimes described as looking like pond algae, can indicate that the baby is getting a lot of the watery foremilk that comes at the beginning of a feed, and less of the fat-rich hindmilk that follows. The high lactose content of foremilk without sufficient fat to slow digestion can result in green, frothy stools and excess wind. Ensuring the baby finishes one breast fully before switching to the other can help rebalance the feed. A lactation consultant can assess the feeding pattern if you are unsure.

Illness

A stomach bug or viral illness can cause green, watery stools. If green diarrhoea is accompanied by fever, vomiting, or the baby seems unwell, contact your GP or call 111.

Dietary causes (in older babies)

Once solid foods are introduced, green stool is often simply a reflection of what the baby has eaten. Purees or finger foods containing green vegetables such as peas, spinach, or broccoli frequently produce green stools. This is normal and no cause for concern.

Orange and red stool

Orange stool in babies is usually diet-related, particularly after the introduction of solids. Foods such as carrots, sweet potato, and squash can produce distinctly orange stools. This is normal.

Red stool is more complex and requires closer assessment. In many cases it is also dietary in origin. Beetroot, tomatoes, strawberries, and certain food dyes can produce red or pink-tinged stools. If the baby recently ate one of these foods, that is the likely explanation.

However, red stool that is not explained by diet could indicate blood in the stool. This can occur from a small anal fissure (a tiny tear from passing a hard stool), from blood swallowed during breastfeeding if the nipple is cracked, or, less commonly, from a problem within the gastrointestinal tract. Bright red blood coating the outside of the stool is more likely to be from an anal fissure. Blood mixed through the stool, or stool that looks like redcurrant jelly, is more concerning and needs prompt medical review. When in doubt, contact your GP or seek urgent advice.

White or pale chalky stool: call a doctor

White, pale grey, or chalky cream-coloured stool is one of the few truly urgent warning signs in a baby's nappy. This colour indicates that bile is not reaching the digestive tract in normal quantities. Bile, produced in the liver and stored in the gallbladder, is what gives stool its brown or yellow colour. Its absence points to a possible obstruction or problem with the bile ducts.

The most serious cause in infants is biliary atresia, a rare condition in which the bile ducts are absent or blocked. It affects approximately one in every 15,000 babies. Biliary atresia is treatable if caught early, but treatment becomes progressively less effective the longer diagnosis is delayed. The NHS and the British Liver Trust both recommend that any baby producing persistently pale, chalky, or white stools should be seen by a doctor as soon as possible.

The Infant Liver Trust operates a stool colour chart specifically for identifying abnormal infant stool colours. This chart has been adopted by health authorities in several countries as a newborn screening tool.

Black stool after the newborn stage

Black stool in a baby past the meconium stage, after the first few days of life, is a warning sign. It can indicate bleeding in the upper digestive tract, such as the stomach or small intestine. This blood becomes dark or black as it is digested and passes through the bowel, producing what is known as melaena.

If your baby passes black stool and is past the first few days of life, contact a healthcare professional promptly. This is separate from stool darkened by iron supplements, which can produce dark green to black stools that are otherwise normal in an iron-supplemented baby. If your baby is on iron supplements, check with your GP or health visitor about what colour changes to expect.

Frequency and consistency: what is normal?

As important as colour is the frequency and consistency of stool. Normal ranges vary widely depending on age and feeding method.

Newborns, especially those who are breastfed, may poop after every feed, meaning eight or more times per day in the early weeks. This high frequency reflects the digestive efficiency of breast milk. Formula-fed babies tend to be at the lower end, often once or twice per day.

From around six weeks of age, many breastfed babies dramatically reduce the frequency of dirty nappies and may go three, five, or even ten days without one. This is normal as long as when a stool does arrive it is soft and the baby is otherwise well. The key distinction between infrequent stools and constipation is the consistency of the stool when it does come. Soft, non-straining stools that arrive infrequently are not constipation. Hard, dry, pellet-like stools that cause distress are.

Frequently asked questions

What colour should newborn poop be?

In the first one to two days of life, newborn poop will be meconium: very dark green, almost black, and sticky with a tar-like consistency. This is completely normal and is made up of material the baby ingested in the womb. By days three to five, as milk feeds establish, the stool transitions to a lighter, brownish-green colour. By the end of the first week, a breastfed baby's stool should be yellow and mustardy, while a formula-fed baby's will be tan to pale brown.

Is green poop in a breastfed baby normal?

Occasionally green poop in a breastfed baby is usually normal, but persistent green frothy stools can sometimes indicate a foremilk and hindmilk imbalance. If a baby feeds for only a short time on each breast, they may get a lot of the watery foremilk and less of the fat-rich hindmilk, resulting in green stools. Ensuring the baby fully drains one breast before switching can help. Persistent green stools alongside poor weight gain or excessive wind are worth discussing with a midwife or lactation consultant.

When is baby poop a medical emergency?

Seek immediate medical attention if your baby's stool is white, pale grey, or chalky (which can indicate a bile duct blockage), if there is bright red blood in the nappy that cannot be explained by a small skin tear or dietary cause, or if a stool is black after the newborn meconium stage has passed (which may indicate bleeding higher in the digestive tract). A hard, distended abdomen or complete absence of stools for more than five to seven days in a newborn also warrants a prompt call to a doctor.

How often should a newborn poop?

In the first few days, most newborns will have several dirty nappies each day. After the first week, breastfed babies often poop after almost every feed, but it is also completely normal for a breastfed baby to go several days without a dirty nappy once past around six weeks of age. Formula-fed babies tend to poop less frequently, typically once or twice a day. What matters most is that the stool is soft and the baby is feeding well and gaining weight. Hard, pellet-like stools may indicate constipation.

Related articles

• Newborn screening
• Breastfeeding basics
• Starting solids around 6 months

Sources

• NHS: Baby poo
• AAP Healthy Children: Stool colour changes
• CDC: Breastfed infant stool
• British Liver Trust: Biliary atresia