Baby Spitting Up Mucus: Is It Normal, Causes and When To Worry

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An immature digestive system or poor valve closure (pyloric sphincter) in the upper end of the stomach is responsible for your baby spitting up mucus or milk. While it is normal for babies to spit up occasionally, it may be a cause for concern if it happens quite often. However, many factors can cause it to happen often, and it can be treated based on the underlying cause.

Read this post to know why your baby spits up mucus and some management options for this condition.

How Normal Is It For A Baby To Spit Up Mucus?

While it is normal for babies to spit up mucus or milk occasionally, you should be concerned if it becomes a repeated occurrence (more than a few times a day). If the mucus contains traces of blood, or you spot signs of distress in your baby, seek medical attention.

So, what could be the possible reasons behind babies spitting up mucus? Read the next section to find out.

Why Do Babies Spit Up Mucus?

It could be concerning to see your baby spit up milk or mucus, but this is a common occurrence until they are 12 months old. They could spit up a clear liquid or regurgitate food that is milky white. This could be due to their immature digestive system. However, there could be other reasons as well. Let’s find out.

1. Overfeeding

As your baby’s digestive system is underdeveloped, it may struggle to handle extra food. So, if you overfeed your baby, they might spit up or vomit the excess food.

If your baby vomits, do not force-feed them to compensate for the vomited food, as it would only lead to more vomiting.

2. Spitting up right after feeding

Sometimes, you might find your baby spitting up clear liquid just after feeding. You might also find spit-ups that are white, milky, or clear after they burp. This could be due to their developing digestive system.

3. Teething

Babies usually start teething between six and twelve months. It can cause major discomfort for the baby. One of the common symptoms of teething is drooling. The salivary reflex is stimulated by eruptions of teeth during teething, which results in excess production of saliva (1).

Sometimes, babies can also spit up the excess saliva in the form of a clear liquid. In case your baby spits up more than usual while teething, look out for occasional coughing or gagging and skin rashes around the mouth, cheeks, chin, and neck area (2).

4. Gastroesophageal reflux (GER)

GER is a condition in which the contents of the stomach flow back into the esophagus. It generally occurs due to the underdeveloped lower esophageal sphincter in babies. The condition occurs in 40–65% of infants between the ages of one and four months.

In the case of GER, you would notice your baby spitting up mucus and vomiting due to the forceful expulsion of gastric material from the mouth. Besides spitting up and vomiting, if your baby cries excessively (colic), has trouble swallowing, feels irritable after feeding, or gags continuously, it could be GER (3).

5. Pyloric stenosis

This is a condition of the gastrointestinal tract that may cause your baby to spit up and vomit. In pyloric stenosis, the lower part of the stomach that connects the intestines (pylorus) narrows, preventing the food from the stomach from entering the small intestine.

This condition affects three out of 1,000 babies in the U.S., and male babies are four times at a higher risk of developing it than female babies. Babies with pyloric stenosis are not born with it but develop it between three and five weeks of life. Although the exact cause is unknown, it is seen in babies whose mothers took antibiotics during the end of pregnancy or breastfeeding.

Along with spitting, you may also notice projectile vomiting, which is characterized by the forceful ejection of breast milk or formula from the mouth, fewer and smaller stools, failure to gain weight, and lethargy (4).

6. Throat infections

Sometimes, throat infections can also lead to the spitting up of mucus in babies. One such infection is epiglottitis, a severe infection of the flap of tissue above the vocal cords. It generally covers the windpipe during swallowing. Along with drooling and spitting, this condition also causes severe sore throat and fever (5). Note that your baby requires emergency care if they have this condition, as it could shut off the airway.

How To Stop A Baby From Spitting Up Mucus

Spitting up mucus or milk is normal in babies and does not need any special attention. It might subside once your baby’s digestive system matures to handle the food. However, if your baby often spits up and shows additional symptoms, consider following the tips mentioned below.

  • Keep your baby’s feeding patterns in mind, and do not overfeed them. One way to deal with this is to decrease each feeding quantity while increasing the frequency of feeding. This would help your baby get the necessary nutrients while giving their immature digestive tract enough time to process food.
  • If the spitting up is due to teething, try to give your baby a frozen teether to chew on, gently massage your baby’s gums with a clean finger, and continue to breastfeed to help soothe their sore gums.
  • To keep GER symptoms in check, try to elevate your baby’s head after feeding, ensure you burp your baby after each feeding, and thicken the formula milk after consulting with your pediatrician.
  • Talk to your pediatrician if your baby is diagnosed with more severe issues such as pyloric stenosis or bacterial infections.
  • If your baby’s nose is filled with mucus, they may not know how to sneeze and get it out. So, when the mucus enters the throat, they might swallow or spit it up. To prevent this, you can suck mucus out of your baby’s nose using a bulb syringe.

When To Call Your Doctor?

Call your doctor if (6)

  • You notice faint blood traces in the spit-up. This could be due to the inflammation of the esophageal tissue. Also, if your baby spits up dark brown blood, you may have to seek medical attention.
  • Your baby spits up milk that turns blue. This could be due to an airway or intestinal obstruction.
  • Your baby is less than 12 weeks, and the spitting up of mucus has changed to vomiting.
  • You notice signs of epiglottitis in your baby.
  • The baby is lethargic and has trouble feeding.

Frequently Asked Questions

1. What does it mean when a baby is spitting and coughing up mucus?

Coughing up and spitting mucus can signify lower respiratory tract infections such as bronchitis. This can be caused by a respiratory syncytial virus (RSV) in infants. High fever and other symptoms can be associated with productive cough in case of pneumonia or more severe infections (7).

2. What does a baby spitting up green mucus mean?

Green mucus indicates that the white blood cells fight against the pathogen, causing infection. Usually, the green mucus becomes clear in a few days. If your baby is coughing up green mucus for more than a few days, they may require antibiotic treatment as per the pediatrician’s prescription (8).

3. Why does my baby persistently spit up mucus?

There can be various reasons for a baby to spit up mucus continuously. Swallowing excess mucus due to allergies and infections can make the baby spit up mucus. Spitting up mucus may resolve as the baby grows older and their digestive system matures.

An immature digestive system could result in the baby spitting up mucus. It is normal if it happens occasionally. However, frequent spitting up may indicate underlying problems. While a few of the reasons could be harmless, like teething or overfeeding, other reasons such as GERD or throat infections could cause complications if not treated promptly. Talk to a pediatrician regarding the causes of the spitting and make changes in their feeding pattern accordingly. With these changes, the spitting up might subside on its own. However, if you notice any other concerning signs, consult a doctor for prompt medical attention.

Key Pointers

  • Babies may spit up mucus due to many reasons, from overfeeding to underlying conditions such as pyloric stenosis.
  • Feeding adequately, burping them, and offering teething toys may reduce some incidences of mucus spitting in babies.
  • Seek medical care if your baby spits up frequently and the remedies are not helping.


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. Alexander KC Leung and C Pion Kao; Drooling in children; Paediatrics Child Health (1999).
2. Your Infant is Teething: Know the Signs and Symptoms; Children’s Hospital Los Angeles
3. Anna Rybak et al.; Gastro-Esophageal Reflux in Children; International Journal of Molecular Sciences (2017).
4. Chapter X.8. Hypertrophic Pyloric Stenosis; Department of Pediatrics, University of Hawaii
5. Sore Throat; Seattle Children’s Hospital
6. Spitting Up – Reflux; Seattle Children’s Hospital
7. Here’s what your baby’s cough could mean; Texas Children’s Hospital
8. The Skinny On Snot: What Your Child’s Mucus Says About Their Health; Health University Of Utah
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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

Dr. Richard Mario Lurshay

Dr. Richard Mario Lurshay is a young and talented pediatrician, well known for his work with children. After completing his post-graduation in Pediatrics, he completed his training in Pediatric Nutrition from Boston University School of Medicine (USA). He is an esteemed Life Member of National Academy of Medical Sciences (NAMS), National Neonatology Forum (NNF) and Indian Academy of Paediatrics (IAP).... more