Diarrhea is something we would rather not have to deal with — even when it happens to cherubic little babies. But diarrhea happens to everyone — once in a while — and babies are certainly no exception.

Occasional baby diarrhea is pretty common (and very normal!). Your new little one is just beginning to explore food and is still getting used to this digestion thing. But too much diarrhea can lead to too much water loss for a tiny baby.

Here’s what to know about your baby’s runny poop and when to ring your pediatrician.

There’s no one answer to what baby poop should look like. Opening a diaper might reveal a rainbow of colors and textures. This is because babies can have different kinds of watery poop or diarrhea at different ages and stages.

In fact, there’s even a color chart to help parents and caregivers figure out what’s going on with a little one’s poops. A rule of thumb for poop: Any earthy color is just fine!

Your newborn’s very first poop is called meconium and doesn’t even smell bad. That’s because it’s not really poop, but just a baby’s way of cleaning out their intestines from all that time in the womb.

Meconium poop is black to green and looks greasy or tarry. You might see a bit of it mixed in with other poop for a day or two more.

After a few days, your baby’s poop will turn into a yellow mustard color. It might be watery and loose, but it’s still not diarrhea unless your baby is passing more poops than normal.

Newborn babies normally have soft, squishy poops, especially if they’re breastfed only. They also poop a lot — sometimes several times a day. So it can be hard to know if they have diarrhea or not.

However, if your infant has stools that are very runny or larger in size — maybe even leaking out of their diaper — and are more frequent than usual, then they have diarrhea.

If your baby is partly or completely formula-fed, they might have less watery or loose poops. Formula milk usually gives babies firmer poops that are light tan in color. Diarrhea in formula-fed babies will still be a bit watery, though the color can vary just as with normal stool.

There are many causes for baby diarrhea. Most of these are common and go away on their own. Baby diarrhea doesn’t usually last long.

In rare cases, diarrhea might be a sign that something’s not quite right, and your baby may need treatment.

Causes in breastfed babies

A medical study on 150 babies found that infants who are breastfed only have less diarrhea than babies who are partly or completely formula-fed. About 27 percent of breastfed babies got diarrhea often while almost 72 percent of babies who were on formula exclusively got diarrhea often.

There are still plenty of reasons why your baby might get diarrhea even if you’re breastfeeding them. These include:

Changes in your diet

If you’re breastfeeding your baby, a change in your diet can trigger diarrhea in your baby. For example, if you eat a lot of spicy food or sugar desserts one night, it might change your breast milk. This can make your baby’s tummy rumble and move along milk too quickly, leading to diarrhea.


If you’re taking medications like antibiotics, these can also get into your breast milk and trigger diarrhea in your baby. Some nutritional supplements like vitamins and protein powders might also leak into breast milk and stir up your baby’s tummy.

While you breastfeed, it’s safe to assume just about everything you consume can change breast milk. Even a tiny change can trigger diarrhea in sensitive baby tummies, though it is not common for this to happen very often.

Causes in breastfed or formula-fed babies

Stomach bug

If your baby suddenly gets diarrhea, they may have a “stomach bug.” Also called the stomach flu and gastroenteritis, the stomach bug is a common culprit in baby diarrhea. It can also cause other symptoms like a vomiting and a slight fever.

If your baby has a stomach bug, they may have diarrhea and other symptoms several times over a 24-hour period. This common baby illness usually goes away on its own as quickly as it began.

Baby meds

Your little one might occasionally need medication if they’re under the weather. Some medications can loosen your baby’s bowels and cause diarrhea. These include antibiotics for bacterial infections and medications for parasite infections.

Some babies may even be sensitive to over-the-counter fever and pain medications for babies.

Changes in your baby’s diet

By the time your baby is about 6 months old, they’re probably very interested in what you’re eating. And you’re likely ready to introduce them to solid foods. This change in diet can throw a wrench into baby’s digestive system.

A baby’s tummy might take some time changing gears from digesting breast milk or formula to dealing with new, solid foods in addition. This can lead to diarrhea until the digestive hiccups are smoothed over.

Other causes in formula-fed babies

Added formula ingredients

Using a certain formula or changing formulas can cause diarrhea in babies. Some babies just find many formulas harder to digest, though this is uncommon. It might take them a little while to get used to a new formula. This can lead to tummy cramps, gas, and diarrhea.

Milk allergy or intolerance

Milk allergy and milk intolerance are two difference things, but they can both sometimes cause diarrhea in babies. However, an allergy is uncommon. Only about 7 percent of babies under 1 year old are allergic to cow’s milk.

This kind of allergy can cause diarrhea, vomiting, or other symptoms right after feeding, or even hours to days later. Most children grow out of this allergy around the age of 5 years old.

Milk intolerance happens when your little one’s stomach can’t digest lactose, the sugars found in milk. Your baby might get this temporarily after having a stomach bug. Your baby might get diarrhea right after feeding even though they were fine with this kind of formula before.

If your baby has trouble with milk-derived formulas, check the label for ingredients like:

  • casein
  • lactose
  • whey

Rare causes for baby diarrhea

Very rare causes of diarrhea include serious illnesses. These causes aren’t common but can cause diarrhea and other symptoms that last for a long time, or don’t really go away at all.

Rare causes of baby diarrhea include:

  • serious large bowel (intestinal) infections (like Shigella colitis)
  • C. difficile infection
  • cystic fibrosis
  • neuroendocrine tumors

If your baby has a particularly bad bout of diarrhea, look out for serious side effects like dehydration. This can sometimes happen to babies because they’re so tiny. Dehydration is especially a risk if your baby has diarrhea and is also vomiting or has a fever.

Call your doctor immediately if your baby has any signs or symptoms of dehydration from diarrhea. These include:

  • dry mouth
  • dry skin
  • refusing to feed
  • feeding only a little
  • more irritable than usual
  • crying without shedding tears
  • weak cry
  • sunken eyes
  • sleepiness
  • not waking up easily
  • floppiness
  • dry diaper for 8 to 12 hours

You can’t always stop or prevent your baby’s diarrhea, but you can help make your little one more comfortable. You can also prevent dehydration and other complications at home.

In most cases, baby diarrhea gets better on its own and your baby won’t need medical treatment. Here’s what you can do at home when your little one has diarrhea:

  • Keep your baby hydrated. Keep breastfeeding if you’re nursing. If you’re formula-feeding, make the formula as normal and feed your baby.
  • Ask your pediatrician about electrolyte drinks for babies like Pedialyte. These can help replace lost fluids and salts when babies have diarrhea. But note: In normal cases of diarrhea, breast milk or formula is enough.
  • Change your baby’s diaper often. Try to keep them as dry as possible to help prevent a diaper rash.
  • If your little one is eating solid foods, give them bits of foods that may help soothe diarrhea. These include:
    • crackers
    • cereal
    • pasta
    • bananas

Avoid the following:

  • foods that can make diarrhea worse, like:
    • cow’s milk, other than the dairy in their formula (you should be avoiding cow’s milk until your child is 1 year old anyway)
    • apple juice and other fruit juices (you should be avoiding these until your child is 2 years old anyway)
    • fried foods
    • spicy foods
  • sports drinks that are made for adults
  • antidiarrheal medication, unless your pediatrician tells you to give it

The two colors that a baby’s (and adult’s) poop or diarrhea should never be are white and red. Call your baby’s pediatrician immediately if you see these colors in your little one’s diaper.

Very light or white poop can be a sign of a liver problem. Red diarrhea or poop can mean there’s bleeding somewhere inside.

Also call your doctor if your baby has severe diarrhea, or more than 10 watery poops a day.

Get medical attention if your baby has other symptoms or signs of illness along with diarrhea. These include:

  • lots of vomiting
  • forceful vomit
  • skin rash
  • fever
  • weight loss
  • not gaining weight
  • red or white poop

Diarrhea and other stomach hiccups — like gassiness — are common in babies. Though baby diarrhea can be a pain for you and your little one, it usually goes away on its own. Most causes of baby diarrhea don’t need treatment.

You can keep your baby comfortable and hydrated at home until the bout of diarrhea passes. In rare cases the diarrhea may last longer than normal. Call your pediatrician if your baby has severe diarrhea or diarrhea that doesn’t get better after 24 hours.