Baby Spitting Up Curdled Milk: What’s Normal, Causes And Treatment

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As a new parent, you may worry if your baby spits up curdled milk. However, milk gets curdled when mixed with stomach acid, which is normal during digestion. Occasionally, babies may spit up curdled or undigested milk as they have an immature digestive system.

Excessive spitting up of curdled milk or any stomach contents is a cause of concern. You may consult a pediatrician in such cases since it could be due to underlying causes that may require medical or surgical care.

Keep reading this post to explore the possible causes and tips to manage the spitting up of curdled milk in babies.

Possible Causes Of Spitting Up Curdled Milk

Babies may spit up curdled milk occasionally without apparent causes. However, excessive spitting up of curdled milk can be due to any of the following reasons (1).

1. Acid reflux

Acid reflux can be a common cause of spitting up curdled milk in new borns and young babies. Immature gastroesophagealsphinctersmay cause stomach contents to come up through the esophagus and reach the mouth.

Feeding in an upright position, offering feeds little and often and keeping baby in an upright position for 20 minutes after feeding may help reduce acid reflux in some babies.

Some babies with severe acid reflux may require food thickeners for breast milk or formula You may seek a pediatrician’s advice to choose the best method to manage acid reflux in your baby. Some may require medications to prevent acid reflux.

2. Food intolerance or allergy

Lactose intolerance or milk allergy could cause frequent spitting up of curdled milk in some babies. A dietician may assist you with allergy investigations and whether you need to cut out certain food groups during breastfeeding.

If formula feeding, switching to specific formulas, such as low-lactose formula or hypoallergenic formula (hydrolysate formula), may improve the baby’s condition.

Some babies may spit up curdled milk if they are drinking cow’s milk. Eliminating cow’s milk from the diet could resolve this problem. You must only introduce cow’s milk once the baby is older than 12 months.

3. Pyloric stenosis

Pylorus is the outlet of the stomach. Pyloric stenosis is a condition where the pylorus is narrowed and obstructed. The condition interferes with the movement of food from the stomach to the intestines. It can cause the baby to regurgitate curdled milk from the stomach.

Babies may have projectile vomiting of curdled milk, no bowel movement or constipation, and weight loss due to pyloric stenosis. You may seek medical care for diagnosis and treatment.

4. Overfeeding

Babies fed more than the required amount tend to spit up curdled or regular milk since their stomach is full. The gastroesophageal sphincters may open due to pressure and cause the backflow of stomach contents in overfed babies.

5. Immature gastrointestinal system

Immature or underdeveloped gastrointestinal structures and functions can be a reason for frequent spit-up in many babies. Newborns and premature babies are more likely to have an immature GI system.

6. Feeding position

Babies fed in lying down positions may quickly spit up when compared to babies who are mostly fed in an upright position. Milk tends to move down promptly in an upright position, and the position may also help keep the esophageal sphincters closed.

Breastfed babies may benefit from being fed in a laid-back breastfeeding position which can help pace the milk flow.

7. Swallowing air

Swallowing air because of a fast milk flow or suboptimal latch to the breast or bottle teat while feeding may increase the chance of spit-up. The gastroesophageal sphincters may open for burping, and babies may spit up milk or curdled milk along with burp.

Try to identify and avoid the possible causes of spitting up curdled milk. Seek medical care if the baby continues to spit up curdled milk regardless of interventions.

What Does Normal Baby Spit-up Look Like?

Spit-up can be whitish in breastfed and formula-fed infants. Older infants who are eating solid foods may have spit-up of other colors, depending on what they eat. Sometimes, babies may spit up saliva or stomach acid that may look like a clear fluid.

A red color and coffee-ground color may indicate bleeding in the stomach or upper gastrointestinal (GI) tract, and yellow or green color can be due to bile or phlegm. You may seek medical care if spit-up has these colors.

When To Call A Doctor?

You may contact the healthcare provider if your baby spits up excess curdled milk or spits up frequently. You may seek medical care for both curdled spit-up and normal spit-up.

Seek medical care if your baby has any of the following conditions with excess spit-up (4).

  • No weight gain
  • Forceful spit-up or vomiting
  • Green or yellow fluid
  • Blood in spit-up or coffee-ground appearance of the spit-up
  • Refuses to eat or drink
  • Blood in stool
  • Breathing problems after spit-up
  • Dehydration
  • Continuous or frequent crying

Stopping or reducing breastfeeding or changing to formula feeding without consulting a pediatrician is not an ideal decision. Spitting up curdled milk can be due to various reasons. The doctor will diagnose the underlying cause and commence the necessary treatment for relief.

Tips To Reduce Spitting Up Curdled Milk

The following tips may help to reduce spitting up curdled milk in babies (2) (3).

  • Feeding in an upright position or laid back breastfeeding position may help to minimize spit-up.
  • Do not overfeed since babies tend to spit up more when the stomach is full.
  • Do not let the baby lay on their stomach immediately after feeding.
  • Manage milk flow or adjust feeding positions if you have an oversupply of milk.
  • Avoid dressing the baby in tight clothes that may put pressure on their belly while feeding.
  • Feed in regular intervals; long gaps between feedings may increase stomach acid build-up.
  • Give medications on time if prescribed.
  • Modify the diet of infants who are on solid food as per recommendations.
  • Breastfeeding mothers may modify their diet as per recommendations.
  • Discuss the necessary surgery with your doctor if spitting up is due to certain conditions, such as pyloric stenosis.

Spitting up of curdled milk can be avoided in many babies. However, if your baby tends to spit up more than usual, you may seek medical care.

Frequently Asked Questions

1. What is the difference between curdled spitting-up and vomiting?

Curdled spitting is when a baby spits a small amount of food. The content gently dribbles from the mouth and may follow a burp. Since the milk had time to mix with the stomach’s acid, it might appear curdled. On the other hand, vomiting looks more forced with discomfort on a baby’s face. While spitting up is normal, vomiting can be due to an illness (5).

2. When do babies stop spitting up milk?

Babies spit up due to their underdeveloped digestive systems. Spitting-up might stop once the baby’s digestive system matures, at the age of one year, around the same time they start to consume solid foods (6).

There could be no serious medical reason for a baby spitting up curdled milk in small amounts. However, if your baby repeatedly spits up excessive amounts of curdled milk, it could be due to underlying conditions such as pyloric stenosis, allergies, reflux, etc. Most babies outgrow this habit as they grow older and have a well-developed digestive system. Nevertheless, if this practice continues in your baby, it is important to identify the cause and resolve them. Contact a pediatrician for proper diagnosis and treatment of the underlying issue.

Key Pointers

  • Babies may occasionally spit up curdled milk for no apparent reason.
  • Contact your child’s doctor if your baby spits up in excess.
  • Breastfeeding in an upright or a relaxed position may assist in reducing spit-up in babies.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. Why Babies Spit Up; Healthy Children; The American Academy of Pediatrics
2. Spitting up in babies: What’s normal, what’s not; St. Clair Hospital
3. Why is my baby spitting up so much breast milk?; Texas Children’s Hospital
4. Spit-Up Concerns; Boys Town National Research Hospital
5. Why Babies Spit Up;
6. Gastroesophageal Reflux in Infants and Children; American Family Physician
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Dr Bisny T. Joseph

Dr. Bisny T. Joseph is a Georgian Board-certified physician. She has completed her professional graduate degree as a medical doctor from Tbilisi State Medical University, Georgia. She has 3+ years of experience in various sectors of medical affairs as a physician, medical reviewer, medical writer, health coach, and Q&A expert. Her interest in digital medical education and patient education made... more

Regina Kincaid

Regina qualified as a midwife in 2005 in Germany and has since worked in maternity care in England and Ireland. She achieved stage 1 of the UNICEF Baby Friendly accreditation as infant feeding lead midwife at Ealing Hospital in London and worked in the lactation team of the National Maternity Hospital in Dublin, Ireland. She did her Neonatal Examination Course... more