Digestive

Blood in Baby's Diaper or Rectal Bleeding

Medically reviewed by Dr. Sarah Chen, MD, FAAP · Board-Certified Pediatrician

Content reviewed against published AAP, AAP, NIH guidelines

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Digestive issues are common in infants and toddlers. If your baby is experiencing blood in baby's diaper or rectal bleeding, here is what you need to know.

The short answer

Finding blood in your baby's diaper can be alarming, but the most common cause is an anal fissure - a tiny tear in the skin around the anus caused by passing a hard stool. This produces small amounts of bright red blood on the outside of the stool or on the diaper. Other common causes include milk protein allergy (in breastfed babies whose mothers consume dairy), swallowed blood from a cracked nipple (in breastfed babies), and constipation. While small amounts of bright red blood from a fissure are common, any significant or persistent rectal bleeding should be evaluated by your pediatrician.

Key takeaways

  • Finding blood in your baby's diaper can be alarming, but the most common cause is an anal fissure - a tiny tear in the skin around the anus caused by passing a hard stool. This produces small amounts of bright red blood on the outside of the stool or on the diaper. Other common causes include milk protein allergy (in breastfed babies whose mothers consume dairy), swallowed blood from a cracked nipple (in breastfed babies), and constipation. While small amounts of bright red blood from a fissure are common, any significant or persistent rectal bleeding should be evaluated by your pediatrician.
  • Usually normal when: A tiny amount of bright red blood on the outside of a hard stool (likely anal fissure)
  • Call your doctor if: Large amounts of blood or blood clots in the stool
“The biggest concern with vomiting is dehydration. Young children can become dehydrated quickly, so it's important to replace fluids. Offer small amounts of an oral rehydration solution frequently.”
— Vomiting in Children, American Academy of Pediatrics (AAP)

Parents everywhere have the same worry. You are doing the right thing by looking into it.

What Parents Should Know

According to AAP, NIH guidelines, finding blood in your baby's diaper can be alarming, but the most common cause is an anal fissure - a tiny tear in the skin around the anus caused by passing a hard stool. This produces small amounts of bright red blood on the outside of the stool or on the diaper. Other common causes include milk protein allergy (in breastfed babies whose mothers consume dairy), swallowed blood from a cracked nipple (in breastfed babies), and constipation. While small amounts of bright red blood from a fissure are common, any significant or persistent rectal bleeding should be evaluated by your pediatrician. At 0-12 months, blood in a young baby's stool is most commonly caused by: milk protein allergy or intolerance (small streaks of blood and mucus in otherwise normal stool), swallowed maternal blood from cracked nipples during breastfeeding, or a small anal fissure from constipation. In breastfed babies, blood-streaked mucousy stools that are otherwise normal in frequency may indicate a cow's milk protein sensitivity passed through breast milk. Always report blood in a young baby's stool to your pediatrician for proper evaluation. It is generally considered normal when a tiny amount of bright red blood on the outside of a hard stool (likely anal fissure). However, you should contact your pediatrician promptly if large amounts of blood or blood clots in the stool.

Sources: [1], [2], [3]

Normal vs. Concerning

Usually Normal
Worth Discussing
A tiny amount of bright red blood on the outside of a hard stool (likely anal fissure)
Large amounts of blood or blood clots in the stool
Blood that resolves once constipation is treated and stools soften
Dark, tarry, or black stools (suggests bleeding higher in the digestive tract)
A one-time episode of streaky blood with an otherwise well baby
Bloody stool with severe abdominal pain, especially if the pain comes in waves (possible intussusception)

By Age

What to expect by age

0-12 months

Blood in a young baby's stool is most commonly caused by: milk protein allergy or intolerance (small streaks of blood and mucus in otherwise normal stool), swallowed maternal blood from cracked nipples during breastfeeding, or a small anal fissure from constipation. In breastfed babies, blood-streaked mucousy stools that are otherwise normal in frequency may indicate a cow's milk protein sensitivity passed through breast milk. Always report blood in a young baby's stool to your pediatrician for proper evaluation.

1-3 years

The most common cause of rectal bleeding in toddlers is an anal fissure from constipation. Hard stools stretch and tear the delicate skin around the anus, causing bright red blood on the stool surface, in the diaper, or on toilet paper. The toddler may cry or resist having bowel movements due to pain. Treatment focuses on softening stools with adequate fluids, fiber, and sometimes stool softeners. Less common causes include bacterial infections, polyps, and inflammatory conditions. If blood is persistent, dark, or mixed into the stool, see your pediatrician.

What to Tell Your Pediatrician

  • Describe when you first noticed blood in baby's diaper or rectal bleeding and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if blood in stool occurs more than once or twice.
  • Mention if blood is mixed into the stool rather than just on the surface.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

What Should You Do?

When to take action

Probably normal when...
  • A tiny amount of bright red blood on the outside of a hard stool (likely anal fissure)
  • Blood that resolves once constipation is treated and stools soften
  • A one-time episode of streaky blood with an otherwise well baby
Mention at your next visit when...
  • Blood in stool occurs more than once or twice
  • Blood is mixed into the stool rather than just on the surface
  • Your breastfed baby has bloody mucousy stools (possible milk protein allergy)
  • Your child has recurrent anal fissures from chronic constipation
Act now when...
  • Large amounts of blood or blood clots in the stool
  • Dark, tarry, or black stools (suggests bleeding higher in the digestive tract)
  • Bloody stool with severe abdominal pain, especially if the pain comes in waves (possible intussusception)
  • Blood in stool with fever, diarrhea, and your child appearing very ill
  • "Currant jelly" stool - dark red, jelly-like stool (possible intussusception - emergency)

What You Can Do at Home

  • Keep track of when you notice blood in baby's diaper or rectal bleeding — noting the time of day, duration, and any triggers can help your pediatrician.
  • Remember that a tiny amount of bright red blood on the outside of a hard stool (likely anal fissure) — this is generally within the range of normal.
  • At 0-12 months, focus on observation rather than intervention unless your pediatrician advises otherwise.
  • Keep your baby upright for 20-30 minutes after feeding. Note any patterns between feeds and symptoms.
  • While monitoring at home, seek immediate care if large amounts of blood or blood clots in the stool.

Baby Constipation

Constipation in babies is defined by hard, dry, difficult-to-pass stools rather than by how often your baby poops. Breastfed babies can go several days without a bowel movement and still be perfectly normal. If your baby is passing soft stools comfortably, even if infrequently, they are likely not constipated.

blood in stool

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Poop Color & Texture Guide

What your baby's poop color and consistency mean, and when to worry.

Guide

When to Call the Doctor

General guide on when to call the pediatrician, visit urgent care, or go to the ER.

Frequently asked questions

Is blood in baby's diaper or rectal bleeding normal?
Finding blood in your baby's diaper can be alarming, but the most common cause is an anal fissure - a tiny tear in the skin around the anus caused by passing a hard stool. This produces small amounts of bright red blood on the outside of the stool or on the diaper. Other common causes include milk protein allergy (in breastfed babies whose mothers consume dairy), swallowed blood from a cracked nipple (in breastfed babies), and constipation. While small amounts of bright red blood from a fissure are common, any significant or persistent rectal bleeding should be evaluated by your pediatrician.
When should I call the doctor about blood in baby's diaper or rectal bleeding?
Large amounts of blood or blood clots in the stool Dark, tarry, or black stools (suggests bleeding higher in the digestive tract) Bloody stool with severe abdominal pain, especially if the pain comes in waves (possible intussusception)
When is blood in baby's diaper or rectal bleeding normal?
A tiny amount of bright red blood on the outside of a hard stool (likely anal fissure) Blood that resolves once constipation is treated and stools soften A one-time episode of streaky blood with an otherwise well baby
What causes blood in baby's diaper or rectal bleeding?
Finding blood in your baby's diaper can be alarming, but the most common cause is an anal fissure - a tiny tear in the skin around the anus caused by passing a hard stool. This produces small amounts of bright red blood on the outside of the stool or on the diaper. Other common causes include milk protein allergy (in breastfed babies whose mothers consume dairy), swallowed blood from a cracked nipple (in breastfed babies), and constipation. While small amounts of bright red blood from a fissure are common, any significant or persistent rectal bleeding should be evaluated by your pediatrician. Common explanations include: A tiny amount of bright red blood on the outside of a hard stool (likely anal fissure). Blood that resolves once constipation is treated and stools soften.
What should I mention to my pediatrician about blood in baby's diaper or rectal bleeding?
You should mention blood in baby's diaper or rectal bleeding at your next visit if: Blood in stool occurs more than once or twice. Blood is mixed into the stool rather than just on the surface. Your breastfed baby has bloody mucousy stools (possible milk protein allergy).
Is blood in baby's diaper or rectal bleeding normal at 0-12 months?
Blood in a young baby's stool is most commonly caused by: milk protein allergy or intolerance (small streaks of blood and mucus in otherwise normal stool), swallowed maternal blood from cracked nipples during breastfeeding, or a small anal fissure from constipation. In breastfed babies, blood-streaked mucousy stools that are otherwise normal in frequency may indicate a cow's milk protein sensitivity passed through breast milk. Always report blood in a young baby's stool to your pediatrician for proper evaluation.
Is blood in baby's diaper or rectal bleeding normal at 1-3 years?
The most common cause of rectal bleeding in toddlers is an anal fissure from constipation. Hard stools stretch and tear the delicate skin around the anus, causing bright red blood on the stool surface, in the diaper, or on toilet paper. The toddler may cry or resist having bowel movements due to pain. Treatment focuses on softening stools with adequate fluids, fiber, and sometimes stool softeners. Less common causes include bacterial infections, polyps, and inflammatory conditions. If blood is persistent, dark, or mixed into the stool, see your pediatrician.
Should I go to the ER for blood in baby's diaper or rectal bleeding?
Seek emergency care if large amounts of blood or blood clots in the stool, or if dark, tarry, or black stools (suggests bleeding higher in the digestive tract). When in doubt, call your pediatrician's after-hours line for guidance.
Does blood in baby's diaper or rectal bleeding go away on its own?
In many cases, blood in baby's diaper or rectal bleeding resolves on its own, especially when a tiny amount of bright red blood on the outside of a hard stool (likely anal fissure).
AAPAAPNIH

References

  1. [1]American Academy of Pediatrics. Blood in Infant Stool. HealthyChildren.org. AAP
  2. [2]American Academy of Pediatrics. Constipation in Children. HealthyChildren.org. AAP
  3. [3]National Library of Medicine. Rectal Bleeding in Children. StatPearls. NIH

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Blood in Baby's Diaper or Rectal Bleeding.

Things to mention

  • Describe when you first noticed blood in baby's diaper or rectal bleeding and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if blood in stool occurs more than once or twice.
  • Mention if blood is mixed into the stool rather than just on the surface.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

Observations to share

  • Blood in stool occurs more than once or twice
  • Blood is mixed into the stool rather than just on the surface
  • Your breastfed baby has bloody mucousy stools (possible milk protein allergy)

Urgent signs to report immediately

  • Large amounts of blood or blood clots in the stool
  • Dark, tarry, or black stools (suggests bleeding higher in the digestive tract)
  • Bloody stool with severe abdominal pain, especially if the pain comes in waves (possible intussusception)

My notes

From ismybabyalright.com — free, evidence-based baby health guides

All content follows our editorial policy and is reviewed against published clinical guidelines.

2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members

Related Resources

Poop Color GuideEmergency ContactsBaby Tracker

Bottom line

Most cases of blood in baby's diaper or rectal bleeding are normal. Talk to your pediatrician if large amounts of blood or blood clots in the stool.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

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Related Digestive Concerns

Baby Constipation

Constipation in babies is defined by hard, dry, difficult-to-pass stools rather than by how often your baby poops. Breastfed babies can go several days without a bowel movement and still be perfectly normal. If your baby is passing soft stools comfortably, even if infrequently, they are likely not constipated.

My Baby's Belly Looks Swollen

A rounded, slightly protruding belly is completely normal in babies and toddlers due to immature abdominal muscles and their proportionally larger organs. However, if the belly becomes suddenly swollen, feels hard and tight, or is accompanied by pain, vomiting, or changes in bowel movements, it needs medical evaluation as it could signal gas buildup, constipation, or rarely, something more serious.

My Baby Has an Anal Fissure (Blood When Pooping)

A small streak of bright red blood on the surface of your baby's stool or on the diaper is most commonly caused by an anal fissure, which is a tiny tear in the skin around the anus from passing hard stool. Anal fissures are very common in babies and toddlers and usually heal on their own with simple measures like keeping stools soft. While this is rarely serious, any blood in your baby's stool should be mentioned to your pediatrician.

Can Antibiotics Damage My Baby's Gut?

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Silent Reflux in Baby

Silent reflux occurs when stomach acid rises into the esophagus and throat but is swallowed back down rather than spit up. Babies with silent reflux may be fussy during or after feeds, arch their back, have hoarse crying, or refuse to eat, but without visible spitting up. It can be harder to diagnose than typical reflux because there is no obvious spit-up.