Why Do Breastfed Baby Poop Smells Bad? Find Out!

As new moms, we have a lot of things to learn about our newborn babies. Isn't it difficult when you see something unusual and begin to get frantic because anything unfamiliar regarding your baby makes you worry? We've all gone through that.


Remember the first time your baby pooped and found a tar-like substance and wondered whether it is normal for breastfed baby poop smells bad or is it something you should worry about? We know how you feel completely. Today, we will discuss about your baby's bowel movement and find out what's normal and what's not.

Stages of Baby Poop

Before Birth

When your baby was still inside your womb, her intestines are already beginning to accumulate poop inside. Her poop consists of body cells, hair, and amniotic fluid. However, she waits until she's born to poop it out. There are cases where a baby poops inside the womb and it can pose health dangers.

First Week

​Once your baby is born, you will notice that within the first 24 hours, your baby will be pooping a lot of tar-like black gooey substance. This is perfectly normal, this is called meconium. Expect her to be pooping a lot because your breast milk acts as a natural laxative.

Pre-solid Food Stage

In the stage where your baby is purely breastfed, the first few months will be a diaper changing chaos. You will notice that breastfed babies poop more - which is a good thing. Her poop will look like a blended mango milkshake, yellow and liquidy.

Babies who are on pure formula will poop less because formula takes more time to digest. Her poop will look more like yellowish or greenish mashed potatoes.

Pre-solid Food Stage

​This is the stage where poop will vary. The food that you introduce to your child will affect the way your baby's poop look like and smell like. Your baby will be pooping less and her feces would be closer to a softer more solid phase.

Is Stinky Poop for Baby Normal?

Newborn baby poop doesn't really smell. It has a mild sour smell but that's about it. In the weeks where your baby already got rid of meconium, her yellowish poop will have a mild sour smell but the smell is pretty much tolerable that even if you fill up your diaper pail, it won’t stink too much.

Why do baby's poop smell?

Smelly poop for babies depends on many things. In the first few weeks of like if your breastfed baby poop smells bad, it may be because of the food you are consuming dairy products. Whatever it is you consume affects your baby's bowel movement, so if you eat a lot of gas-producing food - like broccoli, wheat, and more - your baby will feel gassy too. And where there's gas, there's odor!

Your baby's stool will also reek when your baby takes medication like antibiotics. Antibiotics kill bacteria including the good bacteria in their tummy that makes their poop smell just fine. When your baby has a really foul sour smelling poop, she may be allergic or intolerant to certain foods. But in general, formula fed babies have smellier poop than breastfed babies.

​Colors Tell It All!

​Aside from the smell, the color of your baby's stool can also give you an idea of what is normal and what's not. If your breastfed baby's poop has the following color, then congratulations! Your baby has absolutely a normal bowel movement. Normal baby poop colors are:

  • Mustard Yellow or Orangish
  • Peanut buttery color and consistency or Tan
  • Forest Green is the normal transition from meconium to ordinary poop or your baby is taking iron supplements
  • Brown is normal once your little one starts eating solids
  • Lime Green is nothing to worry about. It's a sign that your baby's breast milk intake is uneven. There is a foremilk/hindmilk imbalance in your make because you either have a too fast letdown, you have an oversupply of milk, or you switch boobs far too often. It will normalize eventually in time.

How to tell if your baby is constipated?

This often happens when your baby already starts eating solid food. Constipation isn't about your baby not pooping on a daily basis; it is in the way your baby’s poop is. Constipation is the state where your baby's poop looks like goat's poop or hard raisins. You might even see traces of blood because constipation can cause wounds on your baby's butt.

If your baby is comfortable even if she doesn't poop for a day or two and her poop still looks like the normal mushy stool, then your baby is fine. It is normal for your little one to pass a day or two without pooping.

How to tell if your baby has diarrhea?

The odor is definitely one factor! You would already get familiar with the way your baby's poop smell. So if there are changes to the normal sour odor of her poop, you should investigate. And the frequency of her poop is twice or thrice as frequent. You may find mucus in your baby's stool when she has diarrhea.

Diarrhea can lead to dehydration. If your baby has diarrhea, sunken eyes or lethargy, a sunken fontanel, very few wet diapers, and a fever (a temperature above 100.4 degrees Fahrenheit), you should immediately consult her pediatrician. Added symptoms would be crying without tears and irritability.

What Factors Affect My Baby's Bowel Movement?

​There are so many things that affect your baby's bowel movement. There are three main causes of why your baby's poop smell and why it looks different at some point. First would be a change in their diet. Once you introduce new food or a new formula, their bowel movement changes.

​The second reason would be due to your food intake as well. If you are breastfeeding, the food you're eating is directly translated into your breastmilk. If your baby has allergies to the food you take, it would also result in a differently smelling poop and a different texture and color.

​The third reason would be medication. If your little one has supplementary medicine like iron supplements, the color and texture of her poop will change.

When Should I Seek Medical Help?

If your breastfed baby's poop smell bad but she's still well and active, there is nothing to worry about. The change in her behavior as well as the change in her bowel movement, and the way the bowel look and smell is telltale signs for something else.

Here are some changes in your baby poop color that should tell you to bring your baby to the doctor:

  • White Creamy or Clay-Colored Poop means that your baby is not digesting food well at all. This means that your little one has a low supply of bile that helps in breaking down food.
  • Frothy Lime Green or Lime Green poop with mucus translates to a parasite in your baby's stomach.
  • Reddish poop is not normal if your child is eating the same food she's been eating in the past. If your baby has hard poop with streaks of red, it's constipation. If her poop is mushy with clumps of red substance, it may be a bacterial infection. But if you fed your baby beets and bright red colored food, then it is nothing to worry about, her poop will really end up being red.
  • Black poop long after the meconium stage means that your baby's poop is mixed with blood during the digestion. Have this checked by your pediatrician.

In Summary

​Smaller babies, in general, don't have smelly poop; it has a mild sour smell but not to the point that it makes you gag. The status of your baby's poop translates to the condition of her digestive system. An explosive horrible smell in your baby's poop can translate to a medical condition that needs to be checked.

If you haven't made any changes in your diet, your baby's diet, or gave your child medication and the following changes occur:

  • Change in color
  • Foul smell
  • Different texture
  • Change of frequency in pooping

Then, your baby needs medical attention. Some may be normal but it is still better to be safe than sorry, right?

4 thoughts on “Why Do Breastfed Baby Poop Smells Bad? Find Out!”

  1. My breastfed baby’s poop was fine, perfectly normal, until I needed to take amoxicillin antibiotics. Since then the poop and the gas smell foul. The poop is also very sticky, although normal mustard-yellow in color. It has been several weeks and no sign of a return to normal. What can I do? Are there probiotics safe to give to a baby to restore the gut flora, for example? Thanks in advance!

  2. My 6 week olds poo is very smelly and gas smells bad too, it didnt smell for the first few weeks but has been smelly since about 3 yrs old, although the colour is fine, she has thrush on her tongue past 4 weeks that I cannot clear with the oral gel prescribed by doctor, would this be the cause of it ? Should I be worried ? Is my diet causing this ? Do you have any advice ? Thanks

  3. Hi, my baby is 8 months old. He’s still being breastfed. He doesn’t like eating solids and has a very fussy time when eating something. His poop is yellow mustard and has a strong vinegar odor. Is that normal?

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