Advice for Blood in a Baby's Stool

Baby having his diaper changed
Rayes/Digital Vision/Getty Images
Table of Contents
View All
Table of Contents

If you notice a small amount of blood in your baby's spit-up or stool, you're likely wondering what's causing it and if you should be concerned. Here's what to do when you see ​this distressing symptom.

What to Look For

In the days ahead, monitor your baby's stool. Blood that appears in baby poop can have several causes, some of which aren't alarming and some that may require medical attention.

Before you assume that what you saw was blood, think about what foods your baby recently ate. Because their digestive systems are immature, the food babies eat may not change very much before it's eliminated. That's why their stools can take on every shade of the rainbow, including red if food like beets and tomatoes were eaten.

Note if the blood is mixed throughout the poop, appears only in one isolated spot, or looks like a red streak or stripe. How the blood appears in the stool may help indicate the source of the problem.

For instance, a streak may indicate that there's a tiny tear in the anal tissue, whereas blood that's more marbled throughout the stool may signal a different kind of problem. If the blood continues to appear in the stool, call your doctor and describe what you're seeing.

Potential Causes 

Here are just a few reasons why your baby may have blood in his stool:

  • Anal fissures: These small tears are the most common cause of blood in baby's stool. They can occur when a baby passes a hard stool or if she has a more runny stool, which abrades the sensitive tissue that lines her anus. It's generally believed that a milk-only diet causes a more runny stool.
  • Food allergy: Babies can be allergic to a protein in the milk their mother drinks and that passes into her breast milk, a condition called allergic colitis. If the baby is very sensitive to milk it can lead to inflammation in the colon that causes his poo to be tinged with blood. Cow's milk is the top allergen, but soy milk and goat milk can also trigger the reaction.
  • Intestinal disorder: Colitis, an inflammation of the inner lining of the colon, and intussusception, which occurs when one portion of the bowel slides into the next, can cause blood in a baby's stool.
  • Intestinal infection: Various bacterial infections, including shigella, salmonella, E. coli, or campylobacter, can cause intestinal inflammation that leads to tiny ruptures that lead blood into your baby's poop.
  • Maternal blood: It is possible that blood from delivery or from your cracked, sore nipples may be ingested while breastfeeding that then shows up in his stool. This isn't harmful to the baby.

When to Call the Doctor

Call your doctor right away if your child appears to be very sick, has abdominal pain, or is crying. Other reasons to call immediately include:

  • A large amount of blood in your baby's stool
  • The stool is black or tarry
  • There was an injury to the anus or rectum
  • You've seen the blood more than twice
  • Your baby has diarrhea
  • Your baby is under 12 weeks old

You can wait to call the doctor for a day during their regular office hours if your baby doesn't have the above symptoms. Try to save a sample of the blood in the stool for testing.


In most instances, the issue is likely the small tear, possibly caused by a particularly explosive poop that you may have noted or by a very hard stool. If this is the case, the blood will likely appear as a spot or a long streak in the stool. These generally heal quickly, but your doctor may suggest lubricating your baby's rectum with a glycerin suppository, using a warm saline bath, or steroid ointment.

If constipation is the cause, explore options for a non-constipating diet. If your baby's issue is not an anal tear, your doctor will be able to advise appropriate treatment once a diagnosis is made.

3 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Bray-aschenbrenner A, Feldenberg LR, Kirby A, Fitzpatrick CM, Josephsen JB. Bloody Stools in a 3-Day-Old Term Infant. Pediatrics. 2017;140(3) doi:10.1542/peds.2017-0073

  2. Gultekingil A, Teksam O, Gulsen HH, Ates BB, Saltık-temizel İN, Demir H. Risk factors associated with clinically significant gastrointestinal bleeding in pediatric ED. Am J Emerg Med. 2018;36(4):665-668. doi:10.1016/j.ajem.2017.12.022

  3. Merck Manual Professional Version. Constipation in Children.

Additional Reading

By Jennifer White
Jennifer White has authored parenting books and has worked in childcare and education fields for over 15 years.