Baby Diarrhea
Medically reviewed by Dr. Sarah Chen, MD, FAAP · Board-Certified Pediatrician
Content reviewed against published AAP, CDC, WHO guidelines
Last reviewed:
Digestive issues are common in infants and toddlers. If your baby is experiencing baby diarrhea, here is what you need to know.
The short answer
Baby diarrhea is defined as a sudden increase in the frequency and wateriness of stools compared to your baby's normal pattern. Breastfed babies naturally have loose, seedy stools, which is not diarrhea. True diarrhea in babies is most often caused by a viral infection and usually resolves on its own, but preventing dehydration is the most important thing you can do.
Key takeaways
- Baby diarrhea is defined as a sudden increase in the frequency and wateriness of stools compared to your baby's normal pattern. Breastfed babies naturally have loose, seedy stools, which is not diarrhea. True diarrhea in babies is most often caused by a viral infection and usually resolves on its own, but preventing dehydration is the most important thing you can do.
- Usually normal when: Your breastfed baby has frequent loose, seedy stools but is feeding well and gaining weight
- Call your doctor if: Your baby shows signs of dehydration: fewer than 6 wet diapers in 24 hours, no tears when crying, dry mouth, sunken fontanelle, or unusual drowsiness
- Varies by age — see the age-by-age breakdown below
“If your child has diarrhea, it's important to give enough fluids to prevent dehydration. Continue to feed your child a normal diet, including formula or breast milk.”
Parents everywhere have the same worry. You are doing the right thing by looking into it.
What Parents Should Know
According to AAP, CDC, WHO guidelines, baby diarrhea is defined as a sudden increase in the frequency and wateriness of stools compared to your baby's normal pattern. Breastfed babies naturally have loose, seedy stools, which is not diarrhea. True diarrhea in babies is most often caused by a viral infection and usually resolves on its own, but preventing dehydration is the most important thing you can do. At 0-6 months, breastfed babies often have very loose, yellow, seedy stools multiple times per day, which is completely normal. Diarrhea in this age group means stools are significantly more watery and frequent than your baby's baseline. In young infants, diarrhea can lead to dehydration more quickly, so monitoring wet diapers closely is essential. It is generally considered normal when your breastfed baby has frequent loose, seedy stools but is feeding well and gaining weight. However, you should contact your pediatrician promptly if your baby shows signs of dehydration: fewer than 6 wet diapers in 24 hours, no tears when crying, dry mouth, sunken fontanelle, or unusual drowsiness.
Normal vs. Concerning
By Age
What to expect by age
0-6 months
Breastfed babies often have very loose, yellow, seedy stools multiple times per day, which is completely normal. Diarrhea in this age group means stools are significantly more watery and frequent than your baby's baseline. In young infants, diarrhea can lead to dehydration more quickly, so monitoring wet diapers closely is essential.
6-12 months
As babies start solid foods, their stool consistency normally changes and becomes more formed. Diarrhea at this age is often caused by viral gastroenteritis or a reaction to a new food. Continue breastfeeding or formula feeding as usual during diarrhea episodes, and offer small amounts of water if your baby is over 6 months.
12-24 months
Toddler diarrhea, also called functional diarrhea, is a common condition where toddlers have multiple loose stools per day but are otherwise healthy and growing well. It is often related to excessive juice or fluid intake. True infectious diarrhea at this age is usually caused by rotavirus or norovirus and typically resolves within 5 to 7 days.
24-36 months
Persistent or chronic diarrhea in this age group may warrant investigation for food intolerances, celiac disease, or other digestive conditions. However, most episodes of diarrhea in toddlers are acute and viral. Keeping your child hydrated with an oral rehydration solution and a normal diet is the recommended approach.
What to Tell Your Pediatrician
- Describe when you first noticed baby diarrhea and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if diarrhea lasts more than a few days without improvement.
- Mention if your baby has diarrhea along with a low-grade fever but is still drinking fluids.
- Bring a list of any questions or observations you want to discuss at the appointment.
What Should You Do?
When to take action
- Your breastfed baby has frequent loose, seedy stools but is feeding well and gaining weight
- Your baby has a few loose stools after trying a new food but is otherwise happy and well
- Your toddler has loose stools but is active, eating, drinking, and growing normally
- Your baby has slightly looser stools during teething but no other signs of illness
- Diarrhea lasts more than a few days without improvement
- Your baby has diarrhea along with a low-grade fever but is still drinking fluids
- You notice undigested food consistently appearing in watery stools
- Your baby has recurrent episodes of diarrhea that seem related to a specific food
- Your baby shows signs of dehydration: fewer than 6 wet diapers in 24 hours, no tears when crying, dry mouth, sunken fontanelle, or unusual drowsiness
- There is blood or mucus in the diarrhea, or stools are black and tarry
- Your baby under 3 months has diarrhea with fever above 100.4 degrees Fahrenheit (38 degrees Celsius)
What You Can Do at Home
- Keep track of when you notice baby diarrhea — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that your breastfed baby has frequent loose, seedy stools but is feeding well and gaining weight — this is generally within the range of normal.
- At 0-6 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 your baby shows signs of dehydration: fewer than 6 wet diapers in 24 hours, no tears when crying, dry mouth, sunken fontanelle, or unusual drowsiness.
Related Resources
Diarrhea Decision Tree
Evaluate diarrhea severity, dehydration risk, and when to act.
Poop Color & Texture Guide
What your baby's poop color and consistency mean, and when to worry.
Month-by-Month Development
Detailed monthly development guides from birth through 24 months.
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 baby diarrhea normal?
When should I call the doctor about baby diarrhea?
When is baby diarrhea normal?
What causes baby diarrhea?
What should I mention to my pediatrician about baby diarrhea?
Is baby diarrhea normal at 0-6 months?
Is baby diarrhea normal at 6-12 months?
Should I go to the ER for baby diarrhea?
Does baby diarrhea go away on its own?
References
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Baby Diarrhea.
Things to mention
- Describe when you first noticed baby diarrhea and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if diarrhea lasts more than a few days without improvement.
- Mention if your baby has diarrhea along with a low-grade fever but is still drinking fluids.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- Diarrhea lasts more than a few days without improvement
- Your baby has diarrhea along with a low-grade fever but is still drinking fluids
- You notice undigested food consistently appearing in watery stools
Urgent signs to report immediately
- Your baby shows signs of dehydration: fewer than 6 wet diapers in 24 hours, no tears when crying, dry mouth, sunken fontanelle, or unusual drowsiness
- There is blood or mucus in the diarrhea, or stools are black and tarry
- Your baby under 3 months has diarrhea with fever above 100.4 degrees Fahrenheit (38 degrees Celsius)
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
Bottom line
Most cases of baby diarrhea are normal. Talk to your pediatrician if your baby shows signs of dehydration: fewer than 6 wet diapers in 24 hours, no tears when crying, dry mouth, sunken fontanelle, or unusual drowsiness.
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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