Types of Diarrhea: When to Worry
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 types of diarrhea: when to worry, here is what you need to know.
The short answer
Diarrhea in babies and toddlers is very common and is usually caused by a viral infection that resolves on its own within a few days. The main danger of diarrhea is dehydration, not the diarrhea itself. Knowing the difference between normal loose stools (common in breastfed babies), mild viral diarrhea, and more concerning types of diarrhea can help you know when to call your pediatrician and when to simply focus on keeping your child hydrated.
Key takeaways
- Diarrhea in babies and toddlers is very common and is usually caused by a viral infection that resolves on its own within a few days. The main danger of diarrhea is dehydration, not the diarrhea itself. Knowing the difference between normal loose stools (common in breastfed babies), mild viral diarrhea, and more concerning types of diarrhea can help you know when to call your pediatrician and when to simply focus on keeping your child hydrated.
- Usually normal when: Your breastfed baby has frequent loose, seedy stools which is their normal pattern, not true diarrhea
- Call your doctor if: Your baby shows signs of dehydration: fewer than 3 wet diapers in 24 hours, no tears, sunken fontanelle, dry mouth, or unusual lethargy
- Varies by age — see the age-by-age breakdown below
“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.”
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What Parents Should Know
According to AAP, CDC, WHO guidelines, diarrhea in babies and toddlers is very common and is usually caused by a viral infection that resolves on its own within a few days. The main danger of diarrhea is dehydration, not the diarrhea itself. Knowing the difference between normal loose stools (common in breastfed babies), mild viral diarrhea, and more concerning types of diarrhea can help you know when to call your pediatrician and when to simply focus on keeping your child hydrated. At 0-3 months, breastfed newborns naturally have very loose, watery stools that can look like diarrhea to new parents. True diarrhea in a young baby is a sudden increase in frequency and wateriness beyond their normal pattern. Because young babies dehydrate quickly, even mild diarrhea in this age group deserves a call to your pediatrician. Watch closely for signs of dehydration: fewer wet diapers, no tears when crying, sunken fontanelle, or dry mouth. It is generally considered normal when your breastfed baby has frequent loose, seedy stools which is their normal pattern, not true diarrhea. However, you should contact your pediatrician promptly if your baby shows signs of dehydration: fewer than 3 wet diapers in 24 hours, no tears, sunken fontanelle, dry mouth, or unusual lethargy.
Normal vs. Concerning
By Age
What to expect by age
0-3 months
Breastfed newborns naturally have very loose, watery stools that can look like diarrhea to new parents. True diarrhea in a young baby is a sudden increase in frequency and wateriness beyond their normal pattern. Because young babies dehydrate quickly, even mild diarrhea in this age group deserves a call to your pediatrician. Watch closely for signs of dehydration: fewer wet diapers, no tears when crying, sunken fontanelle, or dry mouth.
3-6 months
Viral gastroenteritis becomes more common as babies begin to put everything in their mouths. Rotavirus and norovirus are common culprits. Diarrhea from a stomach virus is usually watery, may be green or yellow, and is often accompanied by vomiting and sometimes a low-grade fever. Most viral diarrhea lasts 3-7 days. The priority is maintaining hydration with breast milk, formula, or a pediatric electrolyte solution.
6-12 months
Starting solids can cause temporary changes in stool consistency. True diarrhea at this age is often viral but can also be caused by a food sensitivity or intolerance. "Toddler's diarrhea," characterized by multiple loose stools per day in an otherwise healthy, thriving child, can begin in this age range. If your baby has diarrhea after introducing a specific food, it may indicate a sensitivity to that food.
12-36 months
Toddler's diarrhea (functional diarrhea) is the most common cause of chronic loose stools in children ages 1-3. Children have multiple loose, sometimes mucusy stools per day but are otherwise well, growing normally, and have good appetites. This is benign and usually resolves by age 4. Acute diarrhea from infections, dietary changes, or antibiotics is also common in this age group.
What to Tell Your Pediatrician
- Describe when you first noticed types of diarrhea: when to worry 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 7 days without improvement, especially if your child is losing weight or not growing well.
- Mention if you consistently see blood or mucus in diarrhea stools.
- 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 which is their normal pattern, not true diarrhea
- Your baby has a stomach virus with watery stools for a few days but is still taking fluids and producing wet diapers
- Your toddler has loose stools after eating certain fruits, juice, or high-sugar foods, which resolves when the diet is adjusted
- Your otherwise healthy, growing toddler has 3-6 loose stools per day but no other symptoms (toddler's diarrhea)
- Diarrhea lasts more than 7 days without improvement, especially if your child is losing weight or not growing well
- You consistently see blood or mucus in diarrhea stools
- Diarrhea seems to be triggered by specific foods and you suspect a food allergy or intolerance
- Your child has chronic loose stools and you want to confirm it is benign toddler's diarrhea rather than something else
- Your baby shows signs of dehydration: fewer than 3 wet diapers in 24 hours, no tears, sunken fontanelle, dry mouth, or unusual lethargy
- Diarrhea contains significant amounts of blood, is accompanied by high fever (over 102F/39C), or your baby is unable to keep any fluids down
- Your baby under 3 months has diarrhea of any kind, as young babies dehydrate quickly and need prompt medical evaluation
What You Can Do at Home
- Keep track of when you notice types of diarrhea: when to worry — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that your breastfed baby has frequent loose, seedy stools which is their normal pattern, not true diarrhea — this is generally within the range of normal.
- At 0-3 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 3 wet diapers in 24 hours, no tears, sunken fontanelle, dry mouth, or unusual lethargy.
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 types of diarrhea: when to worry normal?
When should I call the doctor about types of diarrhea: when to worry?
When is types of diarrhea: when to worry normal?
What causes types of diarrhea: when to worry?
What should I mention to my pediatrician about types of diarrhea: when to worry?
Is types of diarrhea: when to worry normal at 0-3 months?
Is types of diarrhea: when to worry normal at 3-6 months?
Should I go to the ER for types of diarrhea: when to worry?
Does types of diarrhea: when to worry go away on its own?
References
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Types of Diarrhea: When to Worry.
Things to mention
- Describe when you first noticed types of diarrhea: when to worry 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 7 days without improvement, especially if your child is losing weight or not growing well.
- Mention if you consistently see blood or mucus in diarrhea stools.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- Diarrhea lasts more than 7 days without improvement, especially if your child is losing weight or not growing well
- You consistently see blood or mucus in diarrhea stools
- Diarrhea seems to be triggered by specific foods and you suspect a food allergy or intolerance
Urgent signs to report immediately
- Your baby shows signs of dehydration: fewer than 3 wet diapers in 24 hours, no tears, sunken fontanelle, dry mouth, or unusual lethargy
- Diarrhea contains significant amounts of blood, is accompanied by high fever (over 102F/39C), or your baby is unable to keep any fluids down
- Your baby under 3 months has diarrhea of any kind, as young babies dehydrate quickly and need prompt medical evaluation
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 types of diarrhea: when to worry are normal. Talk to your pediatrician if your baby shows signs of dehydration: fewer than 3 wet diapers in 24 hours, no tears, sunken fontanelle, dry mouth, or unusual lethargy.
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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