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Why Is There Blood or Mucus In Baby's Stool?

Medically Reviewed by Dr. Gina Jansheski, MD, FAAP
Learn how to tell if baby’s stool is normal in appearance or something to call the doctor about.

Have you ever noticed blood or mucus in your baby’s stool during a diaper change? Are you worried there could be something seriously wrong?

Often, your worries will be just that — worries. There may be times, however, when you will notice something out of the ordinary and can catch a problem early before it becomes a serious issue.

When it comes to any health concerns regarding your baby, it is always reassuring to find a cause and a solution. And if you notice blood or mucus in your baby’s stool, it’s natural to want to get to the bottom of it.

Stools With Mucus

If your baby’s diaper looks like it has been covered in slime, that is probably mucus. Any color stool with shiny strings in it that stretch a little means that mucus is present.

Sometimes there can be a very simple explanation for this, or there can be other underlying issues.

If your baby is exceptionally drooly or has a runny nose, what you found in the stool could have come from undigested mucus that was in the saliva or the nasal passages. That’s because things can move through the digestive tract very rapidly in a baby, especially when they are taking breast milk.

Another thing to think about if you are breastfeeding your baby is the possibility that your baby is getting too much foremilk and not enough hindmilk.

The foremilk has less fat and more lactose in it. It provides carbs, proteins, and vitamins. Hindmilk is much higher in fat along with more calories, and your baby needs both of them to grow.

A lack of hindmilk can cause your baby’s stools to contain mucus. To prevent this, make sure your baby is entirely emptying your breast during a feeding. If this doesn’t happen, next time begin feeding your baby from the breast you last finished on.

It is not uncommon to see mucus in a baby’s stools during the first few weeks of life, then later with drooling and teething, also if your baby is breastfed, or if there is a respiratory tract infection with lots of nasal discharge. The presence of mucus is usually harmless, but it can sometimes be an indication of something more like an infection or food allergy. So if your baby seems ill, is not feeding well, or has other signs along with mucus in the stools, save the diaper and call your baby’s doctor for advice.

Stools With Blood

Finding blood in your baby’s stools can be quite alarming. The last thing you probably want to do is closely examine your baby’s poop, but it can give you some very important hints about what might be going on and help you get to the answer. Here are some very generalized descriptions of the things you might see.

1. Stools With Bright Red Blood

  • Normal poop with blood-tinged mucus and your baby looks fine: This is very often the result of a milk protein allergy.
  • Large, hard poop with slight amounts of red blood and your baby is straining to stool: This could be the result of an anal tear. It usually appears as a streak of blood clinging to the outside of the hard poop, or as little bright red spots in the diaper.
  • Diarrhea mixed with red blood and your baby looks ill: This can be a result of a bacterial infection.
  • Larger amounts of bright red blood whenever you change the diaper and your baby looks normal: This could be from giving your baby beet juice, red jello, or something with red food coloring (which is not recommended), or it can also be from an abnormality of the digestive system that is causing bleeding from the lower part of the intestines.

2. Stools With Blackish Blood

If you notice blood in your baby’s stool that actually almost black in color, this usually means it is blood from a little higher in the intestinal tract that has been digested.

  • Blood from nipples: You might think it a little strange, but if you are breastfeeding there is a simple answer. It occurs when you have cracked or bleeding nipples and your baby is digesting the blood. This will very often appear like black seeds or specks inside of the poop. And it will typically be seen in the first few weeks after birth when you both are adjusting to breastfeeding life.
  • Other bleeding: There are rare cases where this can be the result of some bleeding from the upper digestive tract due to an intestinal abnormality or malformation. This type of bleeding usually happens in larger amounts and more frequently.

It’s always best to be safe rather than sorry, so when you come across any of these or if you are concerned at all, reach out to your baby’s doctor for more insight.

Reasons Blood Or Mucus Appear

There can be many different reasons for blood or mucus in your baby’s stool, but most of them aren’t too serious. There are a few causes that pose a higher threat than others, and give you the feeling there is something not quite right (1).

  • Infection: It is possible the blood or mucus could be a result of an intestinal infection like Salmonella, Shigella, or E. Coli. In this case, you would see that your baby is ill and not feeding well. Other signs you would see are diarrhea, fever, and vomiting.
  • Anal fissures: Blood could be present in your baby’s stools if there is a tiny tear in the lining of the anus. This area is very delicate in babies and it can be torn with the passing of a large, hard stool. You may not even notice it until you look very closely at the area between the little folds of the anal opening.
  • Digestive tract/colon issues: If the blood seems to be continuous or if there is a larger amount, there is more likely to be an issue with the digestive tract or colon. Occasionally, during development, something can be a little out of whack when the intestinal tract is forming. The first sign of it could be bleeding. Sometimes there is a family background of the disorder, or the baby has had an associated problem such as long-term, severe constipation, or has a chronic disease.
  • Intussusception: This is when one portion of the intestine inverts into another. It usually begins with sudden loud bursts of crying and abdominal pain in repeated episodes lasting 15 or 30 minutes with periods of improvement in between them. It is a serious situation requiring immediate medical attention.
    Intussusception is traditionally thought of as abdominal pain associated with “currant jelly stool”, in which the stool looks like red currant jelly.
    Headshot of Dr. Gina Jansheski, MD, FAAP

    Editor's Note:

    Dr. Gina Jansheski, MD, FAAP
  • Colitis: Allergic colitis is when your baby’s immune system overreacts to certain proteins causing inflammation and ulcerations to occur in the lining of the colon. The number one cause of this in infants is cow’s milk protein. It can be from the formula or even from mom’s diet if you are breastfeeding.
  • Breastfeeding: If you are breastfeeding and have a bleeding or cracked nipple, it is possible for the blood from this to be ingested by your baby and to appear in the stools. This is harmless for baby, even though it is definitely painful for you!
  • Iron supplement: Generally, this is not an issue with very young babies, but it is good to know that taking iron can sometimes cause the poop to be dark green to blackish.

Is This an Emergency?

Blood or mucus in the stools can be alarming and it is good to know some of the things that might be causing it.

If you notice blood or mucus in the stools, but your baby is feeding normally and acting happy as usual, just give your baby’s doctor a call to inform them and see if they want to take further action.

If there is blood or mucus and your baby is not feeding well or looking ill, it is best to get in right away with your baby’s doctor or visit the emergency room for an evaluation.

Don’t Panic

It can be scary to know there could be something wrong with your baby, but try to stay calm. If you have to visit the emergency room, reach out to a friend or family member so you don’t have to endure it alone. A little bit of support can go a long way.

The Bottom Line

Finding blood or mucus in your baby’s stool is a cause for concern. Even though there may be a simple explanation, in the end, it is not normal for blood or mucus to appear in the stools, so there could be something going on that isn’t quite right. Your baby’s doctor should be able to diagnose the problem and help you figure out what your next steps should be.

If your baby is not feeding well, has a fever, or seems to be in pain, it is best for you to seek medical attention immediately to see whether or not there is a serious problem.

Save The Diaper

Always save a sample diaper to bring in to your medical professional. Or if you cannot do that, just take a photo with your phone. It always helps to actually see what’s going on rather than working from the description.

It seems as if parenting is always full of surprises, like needing to analyze poop during a diaper change. Sometimes a little investigation into what is going on in the diaper can give you more insight into your baby’s well-being than you had imagined.


Pediatrics: Bloody Stools in a 3-Day-Old Term Infant (2)

Medscape: Pediatric Gastrointestinal Bleeding (3)

NBCI: Approach to milk protein allergy in infants (4)

Headshot of Dr. Gina Jansheski, MD, FAAP

Medically Reviewed by

Dr. Gina Jansheski, MD, FAAP

Dr. Gina Jansheski is a board-certified pediatrician with over 20 years of experience treating infants and children of all ages in many different settings. Dr. Jansheski is the mother to three sons, has sponsored a young girl in India for the past 7 years and has also devoted her time to a new charity that she founded, Helping Hands M.D. feeding street animals in Thailand and India.