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baby's poop smells like vinegar

Baby’s Poop Smells Like Vinegar (What To Know)

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When you have your first baby, you’ll be introduced to a whole new world of fecal colors, consistencies, and, of course, smells. The contents of your baby’s diaper can alert you to food sensitivities and other health concerns, but is a vinegar smell cause for alarm?

A change in the smell or appearance of a baby’s bowel movements most commonly comes from changes in diet, even small ones. Strong, unpleasant odors can be a sign of more serious conditions but usually accompany other noticeable symptoms like impaired growth or respiratory issues. 

Read on to better identify the reasons your baby’s diapers might be smelling like vinegar and what, if anything, you should do about it.

Possible reasons why baby poop smells like vinegar

Depending on whether you breastfeed or formula-feed your baby, their bowel movements should typically smell pretty neutral. Formula-fed baby’s stools tend to have a more pungent smell than a breastfed baby’s. 

Ultimately though, poop smells…even baby poop. Adult or child, your fecal matter is the leftovers of anything you eat or drink. As a result, what your baby consumes can impact the characteristics of their bowel movements. 

baby in diaper

Your stools, colors, textures, and smells can also give some clues as to some other things going on in your body. In particular, if your baby’s poop suddenly starts smelling really bad, it could indicate something beyond diet changes. Stinky poop can also be caused by:

  • Change in diet–Any change in a baby’s diet can change the color, texture, and odor of their bowel movements. This can include changing the formula, introducing formula, and adding solids.
  • Celiac Disease–Celiac Disease refers to an immune response to gluten, which is a protein found in wheat, barley, and rye. It can cause a variety of digestional upsets and impact nutrient absorption, which is particularly concerning for growing children.
  • Chron’s Disease–Chron’s Disease is an inflammatory bowel disease that can impact either the small or large intestine. Chron’s can be very painful and also cause malnutrition. 
  • Chronic pancreatitis–Caused by many things, chronic pancreatitis refers to the long-term trapping of enzymes in your pancreas that leads to pancreas damage. Other symptoms include abdominal pain that gets worse when you eat or drink.
  • Cystic Fibrosis–While most known for its respiratory complications, Cystic Fibrosis is a genetic disease that also impairs the body’s ability to absorb nutrients from food. All babies in the United States are screened for Cystic Fibrosis soon after birth, but the most noticeable symptoms are typically coughing, wheezing, and failure to grow.
  • An intestinal infection–Intestinal infections are common in babies. They stem from viruses or bacteria in the intestines and can cause vomiting or diarrhea. Babies often get them because they put their hands and toys in their mouths. 
  • Poor absorption of nutrients–Malabsorption of nutrients is a characteristic of many of the above-listed conditions. However, it has even more causes, like lactose intolerance or carbohydrate intolerance. Malabsorption happens when the body can’t digest certain foods, and diarrhea is the most prevalent symptom. 

What does it mean when a baby’s poop smells like vinegar?

Changes in smell can be attributed to something as simple as a change in your baby’s diet. Did you change formulas? Or is your baby now trying solids? These could easily be the source of the new smell. 

If your baby’s poop suddenly starts smelling more intense and unpleasant, it could be a sign of something wrong. Of course, whether something smells particularly bad is subjective–some people are more sensitive to smells than others.  Pediatricians specifically warn to keep your nose out for a super sweet smell like maple syrup or a rotten fish smell.

changing baby's diaper

Without other points of concern, like poor growth, extreme fussiness, or signs of allergies, a vinegar smell can just mean that your baby has stinky poop. 

How does the mother’s diet impact a breastfed baby’s poop?

While a breastfeeding person’s diet doesn’t impact the nutritional sufficiency of their milk, it can change the taste. And, if your baby has a food allergy and sensitivity, they can react to the proteins from the trigger foods consumed by the mother that is ultimately passed through the breastmilk. 

Fortunately, only about 3 percent of babies have such an allergy or sensitivity. Dairy is the most common culprit, and you’ll probably see other symptoms like eczema, stomach pain, diarrhea, vomiting, blood or mucus in the stools, and even trouble breathing. 

The breastfeeding person’s food and drink choices can also alter the fatty acid profile of the milk. In extreme situations–like a very dramatic diet change on the mother’s part–this could impact the baby’s bowel movements.

You can try avoiding a certain food for a few days if you think that caused a change in your baby’s bowel movements and report the results to your child’s pediatrician.

Should you be concerned if your baby’s poop smells like vinegar?

If you’ve recently made any changes to your baby’s diet–even small ones–a new change in odor is probably related to those dietary changes. Changing or adding formula and introducing solids can cause differences in your baby’s bowel movements. 

While changes in the smell of the poop can be a sign of the bigger concerns identified above, those conditions all come with more objective and consequential symptoms, like extreme fussiness, failure to grow as expected, or trouble breathing. 

A vinegar smell alone doesn’t indicate a need for immediate action. Symptoms in babies that require emergency medical care include difficulty breathing, unconsciousness, sudden lack of alertness, blue or gray skin or lips, or increasing or persistent pain. 

A non-emergent message or visit to the pediatrician is typically warranted if your baby has sudden changes in appetite or behavior, a persistent fever, vomiting for more than 8 hours, dehydration, constipation, or rashes. 

What should you do if your baby’s poop smells like vinegar?

Typically, a change in odor isn’t alarming unless the new smell is very distinct and like rotten fish or very sweet like maple syrup. Urine or stool that smells exceptionally sweet can be an indicator of Maple Syrup Urine Disease. A strong fishy odor can be a sign of Trimethylaminuria

Report any significant changes in your baby’s bowel movements to their pediatrician. If you or their doctor have any other concerns, like excessive fussiness, poor growth, or respiratory issues, a change in smell could be a piece of the puzzle to identify what’s going on with your baby. 

More than smell, the appearance of baby poop can be a cause for alarm. You should immediately contact your pediatrician if your baby has red, chalk-white, or black dirty diapers.

Red poops, unless you’ve just fed your little one beets, can indicate blood in the stool. That can be a sign of a severe digestive issue. 

Chalky white poops can indicate that your baby isn’t producing bile, which means there’s a liver or gallbladder problem. And, if your baby is older than three days, black, tar-like stools can mean that blood has entered the baby’s digestive tract. 

Finally, if your baby has diarrhea for more than 24 hours, it’s also time to contact the pediatrician. Loose, watery stools typically resolve on their own within a few days, but babies are susceptible to dehydration as a side effect.

Joshua Bartlett
Joshua Bartlett

My name is Joshua Bartlett I run this blog with my wife Jarah. We have more than 11 years of parenting experience including three girls and one boy. I started this blog in late 2018 when I realized that I was dealing with baby-related issues on a constant basis…please read more about me here!

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