Key takeaways: Breastfed baby stools are naturally loose, so diarrhea means a sudden increase in how often or how watery stools are. Viruses are the most common cause. The main risk is dehydration. Keep feeding breast milk or formula, use oral rehydration solution if advised, and watch wet diapers closely. Call for signs of dehydration, blood, or fever in young babies.
Diarrhea is common in babies. Most cases are mild and get better on their own, but babies can get dehydrated quickly.
What Counts as Diarrhea?
Normal baby stools vary a lot. Breastfed babies often have soft, seedy, loose stools. Diarrhea means a clear change: more frequent, more watery stools than usual, sometimes leaking out of the diaper.
Common Causes
- Viruses such as norovirus and rotavirus (most common).
- Bacterial infections from contaminated food or water.
- Antibiotics.
- Food sensitivities or allergies.
- Too much juice in older babies (juice isn’t recommended before 12 months).
From the author
From First Breath to First Birthday is my month-by-month guide to your baby’s first year, written as a NICU and postpartum nurse. My book covers common first-year illnesses and the warning signs that mean it’s time to call the doctor, explained the way I’d explain them at the bedside.
Preventing Dehydration
- Keep breastfeeding or giving formula as usual, often in smaller, more frequent amounts.
- Don’t dilute formula.
- Oral rehydration solution (ORS): your doctor may recommend it for babies with significant diarrhea or vomiting. It has the right balance of sugar and salts.
- Avoid juice, sports drinks, and soda, which can make diarrhea worse.
- Plain water isn’t recommended for babies under 6 months.
Signs of Dehydration
- Fewer wet diapers (such as no wet diaper in 6 to 8 hours, or fewer than usual).
- Dry mouth, no tears when crying.
- Sunken soft spot.
- Unusual sleepiness or fussiness.
Diaper Rash
Frequent stools can irritate skin. Change diapers often and use a thick layer of barrier cream.
Preventing Spread
- Wash hands well after diaper changes.
- Clean surfaces.
- Rotavirus vaccine protects against a common cause of severe diarrhea.
Call your baby’s doctor right away if your baby: is under 3 months with diarrhea, shows signs of dehydration, has blood in the stool, has a fever (100.4°F or higher under 3 months), vomits repeatedly, or seems very unwell. Seek emergency care for a baby who is very sleepy, hard to wake, or has no wet diaper for 8 hours or more.
The Bottom Line
Most diarrhea is viral and passes on its own. Keep feeding, watch for dehydration, and call the doctor for warning signs.
Want more support for your baby’s first year? My book, From First Breath to First Birthday, is available on Amazon.
Related Articles
- Vomiting in Babies: When to Worry
- The Newborn Diaper Guide: Poop Colors, Pee Counts, and When to Worry
- Hand, Foot, and Mouth Disease
Sources
- King CK, Glass R, Bresee JS, Duggan C; Centers for Disease Control and Prevention. Managing acute gastroenteritis among children: oral rehydration, maintenance, and nutritional therapy. MMWR Recomm Rep. 2003;52(RR-16):1-16.
- American Academy of Pediatrics. Diarrhea in babies. HealthyChildren.org. https://www.healthychildren.org
- Centers for Disease Control and Prevention. Rotavirus vaccination. https://www.cdc.gov/vaccines
This article is for general education and is not a substitute for individualized medical advice. Always talk with your baby’s health care provider or your own provider about your specific situation. If you think your baby or you may have a medical emergency, call 911.
