My Baby’s Formula Spit Up Is Brown (What Is Rusty Pipe Syndrome?)

A brown tinge in a baby’s spit-up means that it contains blood. It is common in breastfed babies for the first few days of life as they cough up maternal blood. Blood from the nipples that the baby ingests also causes brown spit-ups. In formula-fed babies, blood in the spit-up may mean that your baby is allergic to the specific formula. 

A small amount of blood that goes with an infant’s spit is not always life-threatening. If your baby appears content, happy and active, then there’s no need to worry about it.

However, you still need to consult a pediatrician and examine your baby to rule out the possible cause. 

Why do babies spit up?

Spitting up is not unusual and is a rite of passage in almost all infants. Infant acid reflux is common for the first three months of life.

It is often due to the baby’s developing digestive system, improper breastfeeding position, and latch, or overfeeding. 

Food sensitivities or chronic infant acid reflux are also possible causes of spit-up.

Spit-ups often occur as drool or a spew but are never forceful or projectile, as seen in vomiting.

Vomiting in excessive volume is a symptom of a medical condition that the pediatrician should check, especially if it happens repeatedly. 

Babies are happy-spitters, and unless they are fussy after the regurgitation, it is no big deal, and your baby is doing just fine. 

What a healthy spit-up looks like?

The color of the baby spit-up may vary, depending on how long after they have their last food. After feeding, it appears white, cream, or yellow with a milky texture.

If it happens a few hours after feeding, it will look like curdled milk or cottage cheese because the milk has already mixed with stomach acid. 

📌 A healthy spit-up should not have many tints in it. 

Yellow spit-up could mean bile and a symptom of gastroesophageal reflux disease (GERD). On the other hand, dark green indicates intestinal blockage and may mean your baby is not digesting his food well.

Pink, red, or brown to black spit-up indicates the presence of blood but is not always worrisome if it does not come with other symptoms. 

What is Rusty Pipe Syndrome?

Seeing pink, red, or brown in your baby’s drool has probably set your panic alarm high.

But take it easy, as there are pretty good reasons why it happens, especially if you are breastfeeding.

The flecks of blood result from a harmless condition called Rusty Pipe Syndrome. The blood that mixes with the breastmilk can alter babies’ poop or spit color. 

Rusty pipe syndrome can occur from the first few days after birth while breastfeeding. It tends to last for up to a week when breastmilk becomes established. 

Rusty pipe syndrome happens when a baby ingests blood from:

  • Cracked and bleeding nipples 
  • Mastitis
  • Breast engorgement or clogged milk ducts
  • Maternal-fetal blood swallowed during delivery

Other causes of brown spit-ups

A happy baby is spitting up baby food

Brown spit-ups that occur a few weeks after delivery and in formula-fed babies come from other causes. The possible reasons may be:

1. Milk protein allergy

Milk protein allergy can irritate the lining of the intestines. It could eventually lead to inflammation and bleeding. The blood can show up in the baby’s stool and spit-ups.

Milk allergy occurs with other symptoms, such as extreme fussiness after feedings, loose stool, hives, watery eyes, and wheezing. 

2. Forceful vomit

On rare occasions, forceful vomiting can tear tiny vessels in the esophagus. It happens if your baby is sick and vomiting profusely.

Don’t worry, the tear will heal itself over time. However, you need to check with the pediatrician about how to manage the vomiting and prevent dehydration properly. 

3. Esophagitis

Another lesser-known cause of brown spit-ups in babies is esophagitis. Esophagitis is the esophagus’s inflammation when exposed to irritating substances.

It could be food allergens, stomach acid from GERD, or medicines like antibiotics.

The treatment plan for esophagitis is eliminating the irritants and allergens and medication for GERD. 

4. Vitamin K deficiency

Newborn babies with Vitamin K deficiency are prone to bleeding for the first few weeks of life. This clotting disorder can cause blood in spit-ups, urine, and stools.

To prevent severe bleeding, high-risk newborns are given vitamin K shots at birth to manage blood clotting. 

When should I take my baby to the pediatrician for brown spit-ups?

Brown spit-up usually clears itself a week after breastfeeding when milk production picks up.

If formula-feeding, talk to your pediatrician if you notice the following symptoms:

  • Persistent spitting up of colored fluid, especially greenish ones
  • Vomiting forcefully
  • Chokes after vomit
  • Extremely fussy
  • The baby has a fever
  • Swollen or distended belly
  • Lethargy
  • Reluctance to feed


My baby is being treated for GERD and is spitting up purple. Is it normal?

Medications for infant GERD like omeprazole or lansoprazole can occasionally cause bluish to purple streaks in baby spit-ups. It is harmful and can indicate that the treatment has a reduced efficacy. 

Should I stop breastfeeding if brown spit-ups do not clear after a few days?

No, there is no need to. Cracked and sore nipples will eventually heal and should clear up blood from the breast milk.

You can manage this through proper breastfeeding position to prevent shallow latch

How is milk protein allergy treated to prevent brown spit-ups?

When the pediatrician rules out milk allergy, he may recommend eliminating cow’s milk protein from the baby’s diet.

Your baby can switch to extensively hydrolyzed protein or hypoallergenic formula. Your baby’s digestive system can break up its protein without causing an immune reaction and heal intestinal inflammation. 


Colored spit-ups in an infant can be scary, but there are harmless reasons why it happens.

If you think your baby is ingesting blood not coming from you, it is always a good idea to talk to a pediatrician.

He can perform tests to identify the causes and possible courses of action to treat it. 

How you respond to the situation should be based on the symptoms and your mother’s intuition and better judgment.

If no other symptoms are present, you don’t have to worry too much about it, as most babies thrive. They will still emerge as the happy and healthy babies that parents and caregivers want them to be. 

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Ann Marie is a licensed nurse in the Philippines. She experienced handling and assisting deliveries of newborns into the world. She also trained in labor rooms and pediatric wards while in nursing school - helping soon-to-be mothers and little kids in the process. Though not a mother by nature but a mother by heart, Ann Marie loves to take care of her younger cousins as well as nephews and nieces during her free time.

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