Diarrhea in Babies

Written by Stephanie Watson
Medically Reviewed by Poonam Sachdev on July 27, 2025
6 min read

You can find a lot of different textures, colors, and smells in a baby’s poopy diaper based on what they’re eating (breast milk, formula, or solid foods). The poop is normally much softer than an adult’s and can sometimes be even softer than usual. But if it suddenly gets much looser or more watery and happens more often — lasting for three or more poops — it may be diarrhea.

Many things can cause diarrhea in babies, including:

  • An infection with a virus, bacteria, or parasite: Babies can pick up these germs through contact with unclean food or water, or when they touch germy surfaces and then put their hands into their mouths.
  • A food allergy or sensitivity to medicines
  • Drinking too much fruit juice
  • Certain medicines, such as antibiotics

Diarrhea makes the body lose too much water and minerals called electrolytes. That leads to dehydration, where the body doesn’t have enough water and nutrients to work like it should. Babies can get dehydrated very quickly — within a day or two after diarrhea starts — and it can be very dangerous, especially in newborns. If they’re 3 months old or younger and have any signs of diarrhea, contact their pediatrician as soon as possible.

Also, call the doctor if your baby, no matter what their age, has diarrhea along with these symptoms:

  • A fever of 102 F or higher
  • Belly pain
  • Blood or pus in their poop
  • Poop that’s black, white, or red
  • Feeling sluggish
  • Throwing up

Also, call your baby’s doctor right away if you notice any signs of dehydration, such as:

  • Peeing less often (fewer wet diapers) and having dark urine
  • Acting fussy or irritable
  • Dry mouth
  • No tears while crying
  • Unusual drowsiness or sluggishness
  • A sunken soft spot on the top of the baby’s head
  • Skin that isn’t as elastic as usual (doesn’t spring back when you gently pinch and release it)
  • Poop that smells worse or different than usual
  • Yellow poop (and if your baby drinks formula, the poop is thick like peanut butter)

The main symptom of diarrhea in babies is loose, watery poop that happens more often than usual (for three or more poops). But sometimes, it can be hard to tell diarrhea from normal baby poop.

Your newborn baby will poop three or four times a day. It’s normal for their poop to be loose, yellow, and seedy (you may see tiny flecks from breastfeeding, which is also normal). After this stage, your baby’s poop will change. It may look thicker — like cottage cheese or applesauce — until they’re about 4 to 6 months old.

Babies who eat formula may have thicker poop from the start.

How many times your baby poops per day can be a clue to how serious their diarrhea is. For example, a mild case of diarrhea in babies may look like pooping up to five times per day. A baby who poops six to nine times per day may have a moderate case. But a baby who poops 10 times per day or more may have a serious case of diarrhea, which can lead to dehydration.

One major hint that your baby’s poop may be diarrhea is if it overflows out of their diaper. Understanding poop colors can also help you figure out if it may be diarrhea.

Baby poop changes color, and that’s sometimes a concern for parents. But for the most part, it needn’t be.

The poop color timeline works like this: Yellow means milk is moving through the baby’s system quickly. When the process slows down, poop becomes green. When it gets even slower, poop turns brown.

Baby poop colors of concern

The main colors that should prompt an immediate call to the pediatrician are white, red, and black.

White poop can point to an infection or a problem with bile, which is a fluid made by the liver that helps with digestion. Black poop is a sign of digested blood. Red suggests fresh blood that could be coming from the colon or rectum.

Sometimes, newborns whose parents’ breast skin is cracking swallow the parent’s blood while feeding, which comes through their stool. That’s no cause for alarm, and your doctor may be able to do a test to tell who the blood belongs to.

Occasionally, green, mucus-like poop can be caused by a virus commonly seen in babies. If your child has green poop and symptoms of diarrhea, fever, or irritability, call your pediatrician.

Doctors usually don’t recommend over-the-counter diarrhea medicines for children. But your doctor might prescribe an antibiotic for a bacterial infection or an anti-parasitic drug for a parasite infection.

Babies with severe diarrhea who get dehydrated will need to go to a hospital to get fluids through an IV in their veins.

The doctor might recommend that you give your baby an oral rehydration solution. These products, which you can buy at the supermarket or drugstore, have fluids and electrolytes and can prevent or treat dehydration.

If your child eats solid foods, the doctor might recommend switching to bland, starchy foods like strained bananas, applesauce, and rice cereal until the diarrhea stops. If you’re nursing, you might need to adjust your diet to avoid any foods that could trigger diarrhea in your baby.

Babies with diarrhea should avoid eating anything that can make it worse, including:

  • Greasy foods
  • High-fiber foods
  • Dairy products such as milk and cheese
  • Sweets such as cake, cookies, and soda

Diarrhea that’s caused by a viral or bacterial infection is very contagious. Wash your hands with warm water and soap every time you change your baby’s diaper to prevent the infection from spreading. Keep the diaper-changing area clean and disinfected. Keep your child home from day care until they get better completely.

How to stop diarrhea in babies fast

There’s no way to immediately stop diarrhea in babies. Older kids can take some over-the-counter medicines for diarrhea with a doctor’s approval, but these drugs can be dangerous for babies. Usually, you just have to wait it out.

Baby diarrhea is when your baby’s poop gets looser or more watery, and this lasts for three or more poops. Infections, allergies, and certain medications can all cause diarrhea in babies. If your baby has diarrhea, watch out for signs of dehydration. Call their doctor if they have diarrhea and: 

  • Their poop is white, red, or black.
  • They’re 3 months old or younger.
  • They have a fever or throw up a lot.

In most cases, baby diarrhea will go away once it runs its course.

Here are some commonly asked questions about baby diarrhea. 

Can a baby have diarrhea and not be sick?

Yes, a baby can have diarrhea without being sick. Other reasons your baby may have diarrhea include certain medications, such as antibiotics, allergies and sensitivities, and drinking too much fruit juice.

What stops diarrhea naturally?

There’s nothing that immediately stops baby diarrhea naturally. It usually takes time for the diarrhea to run its course. But if your baby eats solids, their doctor may recommend switching to more bland, starchy foods until the diarrhea stops.