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Is your baby spitting up curdled milk? Or simply spits up a lot?

Let’s go through why a baby spits up, what the curdled milk means, and when the spitting up or vomiting may indicate something isn’t quite right. Learn what to do in each situation.

baby spitting up curdled milk

The information in this article is provided by Medical Doctor Janina Kong. The purpose is to provide examples and knowledge to help parents dig deeper into their baby’s situation, not to offer a complete picture or a possible diagnosis.

Mom’s question:
My baby boy is 5 weeks old. He is eating 4 oz every 3-4 hours. He is spitting up a lot. He was on breast milk, but after he was spitting up what looked like curdled milk, his doctor said to try formula. He is doing the same thing, so switching to formula didn’t help at all. I’m not sure what to try now.

Brandi (Sparr, FL)

Baby Spitting Up Curdled Milk, Spits Up A Lot or Vomits: Reasons & Remedies

What Does Normal Baby Spit-Up Look Like

normal baby spit-up

For babies that are fully breastfed or formula-fed, normal baby spit-up will look just like the formula or milk that he or she just had or may appear more or less curdled.

The milk becomes curdled when mixed with the acidic stomach fluid. So, a baby spitting up curdled milk in itself is completely normal. Many babies spit up a bit of curdled milk now and then.

If the baby swallows the milk and it is mixed with the stomach fluids, it will come back up curdled. If your baby spits up immediately after swallowing, the milk will return like regular milk.

Baby Spit-up Color

As you have already noticed, baby spit-up is likely to be whitish if the baby is on formula or breastmilk. Once solid foods are introduced, the spit-up color will depend on what the baby is eating.

However, there are a few colors to watch out for:

Red or coffee-ground color usually indicates blood. This may need to be addressed immediately by a doctor.

Yellow or green spit-up could mean that your baby is either vomiting phlegm or bile, indicating that your baby is ill.

Babies can also spit up clear liquid, which is usually less of a concern. The spit-up can be saliva or stomach content, indicating acid reflux or possibly pyloric stenosis, which you can read more about below.

But again, a baby spitting up curdled milk is not in itself an issue.

Why do most babies spit up even if they are not ill?

It is normal for infants to spit up, especially after feeding or during burping. This is often due to the immaturity of their lower esophageal sphincter or the LES, gastroesophageal reflux, wherein the abdominal contents flow back up to the esophagus; hence the infant spits up.

Another possible cause is aerophagia or swallowing too much air instead of milk.

And lastly, spitting up can also be caused by overstimulation of the infant during mealtime.

These events may occur in young babies, and they are common. Babies usually outgrow reflux as they grow older, while aerophagia can be addressed by positioning the infant properly during feeding and, lastly, keeping mealtimes more peaceful and not “bouncy”.

When Do Babies Stop Spitting Up?

In general, spitting-up peaks at around 4 months and then stops at some point between 6 months and 12 months of age. Most babies more or less stop spitting up when they have become strong enough to sit up without support.

Unless there are specific underlying problems, you can say that generally, when babies can tolerate the amount of milk that they ingested, they don’t spit up anymore. So an infant that turns away from the breast or feeding bottle on his own will not spit up, considering that they are burped and held upright for 30 minutes or so right after feeding.

Is my Baby spitting up or vomiting?

This is a very relevant question since spitting up is considered normal in many cases, while vomiting is always associated with illness.

Vomiting is more forceful than spitting up and involves more than just a couple of tablespoons of stomach contents. Vomiting can be a sign of a viral infection in the stomach, a reaction to something the baby ate, or another gastrointestinal problem.

  • While spitting up is an easy backflow of stomach contents to the esophagus and into the mouth, vomiting is the forceful, voluminous backflow of stomach contents and tends to be projectile. Vomiting is usually associated with infections, allergies, and abdominal obstruction.
  • A spit-up is usually just a few milliliters of the stomach contents, while vomitus may be the whole of what you consumed at a time.

9 Reasons for Excessive Spitting Up of Curdled Milk in Babies

Here are a few possible reasons for excessive spitting up of curdled milk:

1. Lactose Intolerance

Lactose intolerance is a common condition for infants. You can shift your formulas to low-lactose milk or lactose-free formulas. Sometimes, they can outgrow this, while others may not.

You will find symptoms of lactose intolerance in this post.

You can try a low-lactose formula to help your baby if he is lactose intolerant.

2. Cow’s Milk Allergy

Cow milk allergy is a common childhood allergy. It occurs in 7% of babies under 1 year old but often resolves by 5 years old.

It can lead to an immediate or delayed reaction when consuming cow’s milk. For the immediate type of CMA, the infant experiences symptoms right after introducing the cow’s milk. In contrast, for the delayed type of reaction, the symptoms can be seen after several hours or days after the introduction of CM. The baby may experience one or more symptoms:

  1. rashes on the face or eyelids
  2. swelling of the face, lips, or around the eyes
  3. vomiting, abdominal colic, diarrhea, stomachache
  4. nasal congestion or runny nose
  5. more severe symptoms include: wheezing or difficulty breathing and swelling of the throat (these red flags indicate a trip to the emergency room ASAP!)

For a baby with cow’s milk allergy, a type of formula that may work is hydrolysate formula, which is hypoallergenic.

Remember that it is possible to continue breastfeeding a baby allergic to cow’s milk! All you have to do is eliminate cow’s milk from your diet.

3. Acid reflux

Another possible cause is acid reflux. This is common among newborn babies, where gastric juices containing acid can travel from the stomach to the throat. Continuing breastfeeding is still recommended. Give frequent small feedings. Set him in an upright position right after feeding, and make sure to burp him.

Switching to formula can sometimes help slightly since the formula is a bit thicker than breast milk. This is probably why the doctor suggested it. But it is a fairly minor or no difference, as in your case!

You’ll find several tips for feeding a baby with reflux here.

Learn more about foods to eat and avoid while breastfeeding here.

There is also some medication available for severe acid reflux.

No one can tell if your baby has reflux without examining him, and there may be other reasons for his spitting up.

4. Feeding position and swallowing of air

Positioning during feeding is important since the baby’s LES are immature.

Keep your baby’s head elevated when feeding so the milk flows directly down to the esophagus and the stomach. Keeping his lower extremities higher than his head can cause a backflow of the contents to his esophagus. Also, this can eliminate aerophagia, which can also cause spitting up.

Keeping him in an upright position after feeding is also helpful in keeping the milk down and actively preventing any reflux from happening. Keep him in this position until he burps.

5. Overfeeding

Babies have small stomachs that can only accommodate a few milliliters per feeding. But sometimes, they become overzealous in feeding and do not release the breast from their latch.

When you notice your baby spitting up after feeding or while burping and grunting while sleeping, this is usually a sign of overfeeding. Hence, it is still advisable to give them frequent small feedings, to feed on demand, and to always keep them upright right after feeding.

6. Immature gastrointestinal system

As already mentioned, infants have less developed gastric organs. The lower esophageal sphincter, or LES, is still immature, and can weakness of this sphincter can cause reflux or spit-up. A baby may spit up to 10 to 12 times daily, which is still considered normal.

7. Pyloric Stenosis

Pyloric Stenosis is when the stomach outlet is too narrow for the foods to travel into the intestines. It usually presents with projectile vomiting of milk that may or may not be curdled and an olive-shaped mass near the umbilical area. This condition needs treatment and surgery. (You can read more about pyloric stenosis at

This video presents an explanation of pyloric stenosis:

Understanding Pyloric Stenosis

8. Duodenal Atresia

Duodenal Atresia is another anatomical abnormality that can present with vomiting shortly after birth. In this case, there is a closure in the first part of their small intestines.

Duodenal Atresia is rare, and the cause is unknown. 1 in 3 cases occurs in babies with Down syndrome.

You can watch the video below to learn more about the condition:

Duodenal Atresia Mnemonic

9. Intestinal malrotation and volvulus

Another condition is intestinal malrotation. It is a birth defect and happens when your baby’s intestine doesn’t turn as it should. This can result in the intestine getting twisted (called volvulus), which can cause a blockage.

This usually presents with abdominal distension and bilious vomiting.

There are more anatomical abnormalities that can present with vomiting or spitting up. The best thing to do is still to call your doctor.

10. Infection

A neurological or gastrointestinal infection can present with spitting up or vomiting. Increased intracranial pressure can press on the brain’s vomiting center, causing the baby to spit up more frequently than normal. Acute gastroenteritis can cause vomiting and is usually accompanied by watery stools.

These situations warrant medical consult the earliest possible time. It is important to avoid dehydration since infants are so fragile to infections like these.

This is not a full list, of course, but some examples. It may very well also be that nothing is wrong with your baby and that he simply is a baby who spits up a bit more than the average infant. If your baby is gaining weight and isn’t in pain, he will likely be fine.

Warning Signs of Excessive Spitting Up in Babies

baby spitting up curdled milk warning signs

You and the doctor may have misunderstood each other because it should be the excessive spitting up rather than the curled milk that is the main problem.

Here are some indicators from Mayo Clinic of problematic excessive spitting up in babies:

  • Your baby isn’t gaining weight
  • The spit-ups are forceful, more like real vomiting
  • The spit-up contains green or yellow fluid
  • Your baby spits up blood or material that looks like coffee grounds (which is likely to be blood, and in this case, you need to take your baby to a doctor immediately)
  • Your baby refuses to eat repeatedly
  • There is blood in his or her poop
  • Your baby has difficulty breathing or other signs of illness (again, call the Dr or an ambulance, depending on the situation)
  • Spitting starts late – at age 6 months or older (this could, for example, be due to a food intolerance)
  • If your baby cries a lot – for more than three hours a day and is more irritable than normal
  • Shows signs of dehydration and has fewer wet diapers than usual

It is always imperative to consult your doctors when sudden changes in your babies’ diet, activities, milestones, and habits occur. Babies are prone to infection and are very vulnerable when they get sick. Breastfeeding is still the best source of antibodies for babies up to six months of age.

How to reduce a baby’s spitting up of curdled milk?

First of all, make sure there are no medical reasons for his spitting up, and again, remember that it is not the curdled milk that may be a problem, but how much your baby is spitting up/vomiting and his or her health in general.

If you believe any of the above reasons may be relevant to your baby, consult a doctor.

If the spitting up is caused by less concerning reasons, such as how your baby is fed, his age, mild acid reflux, etc., then here are some tips to prevent him from spitting up:

  • Feed your baby before she is starving. A hungry baby will feed more aggressively and risk swallowing air or overfeeding.
  • Burp frequently.
  • Feed in smaller portions (but more frequently).
  • Feed in a more upright position.
  • Consider low-lactose milk formula or lactose-free milk formula (if your baby is formula-fed).
  • Limit active playing, like bouncing or tummy time, for 30 minutes after feeding. Keep his meal times peaceful.


So to conclude, it is most often normal and without any worries when a baby is spitting up curdled milk. This is true for both breastfed and formula-fed babies. In most cases, it is just due to the milk reacting with the stomach fluids.

However, excessive spitting up of curdled milk – or excessive spitting up in any case – can be a sign of illness. 9 possible issues have been explained in this article. If you notice other signs of illness too, as explained above, or if you simply feel that your baby’s spitting up is too excessive, don’t hesitate to discuss the matter with a doctor.

Good luck!

Read Next

Research References

Hey, parents, is your baby spitting up curdled milk too? Please help this mom by commenting below! Or share your own thoughts and worries!

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This Post Has 4 Comments

  1. Julie

    My daughter spit up all the time when she was
    first born until about 8 months. I only breast fed, and I was worried
    she was spitting up almost everything that was going in. We found the
    problem to be reflux, and although she continued to spit up after the
    medicine it wasn’t as much. Once you start her on foods she will be
    better, but don’t stop breastfeeding!!

  2. Linda

    I think it’s very sad that a professionally
    trained person such as a doctor would tell a mother not to breastfeed
    her child because of spitting up. There are many factors…such as a cow
    milk intolerance in your milk…so you would need to cut out diary

    Since you changed from breastmilk to formula…then the problem
    would not stop there because formula is made mostly from cow milk. I
    would advise switching back to breastmilk which can help your child
    recover inside and out when dealing with problems in this big world such
    as allergies. If you do not plan to switch back i would suggest a goat
    milk formula base (goat milk digests in the human system within 2-4
    hours…cow milk takes 8 and more) or at least try an organic formula or
    soy based. Although these can be a little more, your baby would greatly
    benefit from it.

    Good luck and my advice it to find another
    pediatrician! It has been medically proven for a very long time that
    breast milk is what was designed for the infants ultimate help and
    support during life. Babies do not even develop an immune system alone
    for the first 6 months of life, they rely on yours to fight for them
    during that time. Good luck!

  3. Just me

    Okay, if the baby is spitting up a lot I
    would take the formula down a little bit like to 3.5 oz. My babies are
    almost 4 months old and take 4 oz. every three hours. I do believe that
    is too much for a five week old. Good luck!

  4. Umul

    .My baby is 3 month old.In his 2nd month he used to strain and cry,doc said he has colicaid for which doctor has prescribed colicaid.That helped.Recently 2 weeks back he vomited curdled milk and at times it used to be mixture of water and curdled milk or at times just water.Doc said he has reflux nd prescribed Domstal 1.5 ml 4 times a day for 5 days but i jst gave him for 2 days cos he seemed better.But since yesterday he is throwing up again. :(