A newborn’s diaper is a colour chart you never asked for. In the first weeks the contents run through black, green, mustard and tan — and almost all of it is normal. Only three colours mean “call today”: pale, red, and black (once the early days are past). Here’s the whole range, colour by colour.
The normal arc: meconium to milk stool
Newborn poop changes character over the first week as feeding gets going:
- Days 1–2 — meconium. Black or very dark green, sticky and tar-like, almost odourless. It’s the gut clearing what built up before birth.
- Days 3–4 — transitional. Lighter, greenish-brown and looser, as milk replaces meconium.
- From milk in — milk stool. Breastfed: mustard-yellow, soft, often seedy, mild-smelling, sometimes runny. Formula-fed: tan to brown, pastier, with a stronger smell.
The full colour guide
| Colour | Usually means |
|---|---|
| Black, sticky (first days) | Meconium — normal |
| Greenish-brown (day 3–4) | Transitional — normal |
| Mustard-yellow, seedy | Breastfed milk stool — normal |
| Tan to brown | Formula milk stool — normal |
| Bright or grass green, frothy | Often normal — fast flow or a passing bug |
| Dark green | Iron drops or iron-fortified formula — normal |
| Orange | Normal pigment variation |
| Pale, white, clay or chalky | Call your doctor today |
| Red, or red streaks (blood) | Call your doctor today |
| Black after about day 5 | Call your doctor today |
The three colours you don’t ignore
Most shades are just diet and digestion. These three are worth a same-day call, even if your baby seems well:
- Pale, white, clay or chalky. Stool gets its colour from bile; consistently pale or putty-coloured stool can mean bile isn’t reaching the gut, which needs checking promptly.
- Red. Fresh blood, or red streaks. Sometimes it’s harmless — a breastfeeding mother’s cracked nipple, or a tiny fissure from a hard stool — but blood always earns a call.
- Black after the meconium has cleared. Black in the first days is meconium; black that appears again after about day five can be digested blood. (Iron supplements also darken stool — mention what your baby is taking, but still call.)
Texture, mucus and how often
Colour is only half the picture — texture and frequency fill in the rest:
- Seedy, grainy, soft is the classic breastfed stool. Pastier and firmer is typical of formula.
- A little mucus (stringy or slimy) now and then can be normal; lots of it, or mucus with blood, is worth a check.
- Watery, explosive and much more frequent than usual can be diarrhoea — the real risk is dehydration, so watch the wet diapers.
- Hard, dry pellets with straining is constipation — uncommon in exclusively breastfed babies, more likely once formula or solids come in.
- How often varies enormously: breastfed newborns often go after most feeds, but after about six weeks may go several days between soft stools — that’s fine if the stool is soft and your baby is comfortable.
When to call a professional
Contact your pediatrician, family doctor, or health visitor the same day for:
- Any pale/white, red, or black-after-day-five stool
- Watery diarrhoea, especially with fewer wet diapers, a dry mouth, or unusual sleepiness
- No stool together with a hard, swollen belly, vomiting, and distress
- Blood, or mucus that keeps appearing
This is general information, not medical advice. Every baby is different — if a colour worries you, photograph the diaper and ask the people who know your baby’s history.
Colour is the other half of how many wet and dirty diapers your baby has — together they’re the clearest read you get on how feeding is going. Noting the odd unusual colour as it happens means that when the doctor asks “what did it look like?”, you have an answer instead of a guess.