Baby Foamy or Frothy Poop
Medically reviewed by Dr. Sarah Chen, MD, FAAP · Board-Certified Pediatrician
Content reviewed against published AAP, AAP, CDC guidelines
Last reviewed:
Digestive issues are common in infants and toddlers. If your baby is experiencing baby foamy or frothy poop, here is what you need to know.
The short answer
Foamy or frothy poop in babies is usually caused by excess gas in the stool and is most commonly seen in breastfed babies who may be getting more foremilk (the thinner, lactose-rich milk at the beginning of a feed) relative to hindmilk. It can also occur with a mild stomach bug or a food sensitivity. In most cases, it is not a serious concern and resolves with simple feeding adjustments.
Key takeaways
- Foamy or frothy poop in babies is usually caused by excess gas in the stool and is most commonly seen in breastfed babies who may be getting more foremilk (the thinner, lactose-rich milk at the beginning of a feed) relative to hindmilk. It can also occur with a mild stomach bug or a food sensitivity. In most cases, it is not a serious concern and resolves with simple feeding adjustments.
- Usually normal when: Your breastfed baby has occasional frothy stools but is feeding well and gaining weight normally
- Call your doctor if: Foamy, watery stools are very frequent and your baby shows signs of dehydration such as fewer wet diapers, no tears, dry mouth, or 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 guidelines, foamy or frothy poop in babies is usually caused by excess gas in the stool and is most commonly seen in breastfed babies who may be getting more foremilk (the thinner, lactose-rich milk at the beginning of a feed) relative to hindmilk. It can also occur with a mild stomach bug or a food sensitivity. In most cases, it is not a serious concern and resolves with simple feeding adjustments. At 0-3 months, foamy, frothy poop in young breastfed babies is most often related to a foremilk-hindmilk imbalance. If your baby is not draining the breast fully before switching sides, they may get more lactose-rich foremilk, which can ferment in the gut and produce gas and frothy stools. Try allowing your baby to finish one breast before offering the other. Foamy stools can also appear green. It is generally considered normal when your breastfed baby has occasional frothy stools but is feeding well and gaining weight normally. However, you should contact your pediatrician promptly if foamy, watery stools are very frequent and your baby shows signs of dehydration such as fewer wet diapers, no tears, dry mouth, or lethargy.
Normal vs. Concerning
By Age
What to expect by age
0-3 months
Foamy, frothy poop in young breastfed babies is most often related to a foremilk-hindmilk imbalance. If your baby is not draining the breast fully before switching sides, they may get more lactose-rich foremilk, which can ferment in the gut and produce gas and frothy stools. Try allowing your baby to finish one breast before offering the other. Foamy stools can also appear green.
3-6 months
Foamy stools may continue if the foremilk-hindmilk balance issue persists, but many babies outgrow this as feeding patterns regulate. If foamy stools are accompanied by significant gas, fussiness during or after feeds, and slow weight gain, consulting a lactation specialist can be very helpful. In formula-fed babies, foamy stools can sometimes indicate a sensitivity to the formula.
6-12 months
As babies start solid foods, foamy stools become less common. If they do occur, they may be related to a specific food that causes gas or mild digestive upset. A stomach bug can also produce foamy, loose stools temporarily. If foamy stools are a new development that persists, mention it at your next pediatrician visit.
12-36 months
Foamy stools in toddlers are less common and most often related to a viral illness causing temporary diarrhea. Lactose intolerance, though uncommon in children under 3, can cause foamy, gassy stools after consuming dairy. If your toddler has persistent foamy stools, especially with other digestive symptoms, discuss it with your pediatrician.
What to Tell Your Pediatrician
- Describe when you first noticed baby foamy or frothy poop and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if your breastfed baby consistently has foamy green stools and seems fussy or uncomfortable during feeds.
- Mention if foamy stools are accompanied by poor weight gain or slow growth.
- 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 occasional frothy stools but is feeding well and gaining weight normally
- Foamy stools appear during a mild cold or stomach bug and resolve within a few days
- Your baby has some frothy stools along with normal-looking stools
- Foamy stools improve when you adjust breastfeeding technique to let your baby fully drain one breast before switching
- Your breastfed baby consistently has foamy green stools and seems fussy or uncomfortable during feeds
- Foamy stools are accompanied by poor weight gain or slow growth
- Your baby has foamy, mucusy stools that persist for more than a week
- You suspect a food allergy or intolerance may be causing the foamy stools
- Foamy, watery stools are very frequent and your baby shows signs of dehydration such as fewer wet diapers, no tears, dry mouth, or lethargy
- Foamy stools contain blood or significant mucus along with fever or vomiting
What You Can Do at Home
- Keep track of when you notice baby foamy or frothy poop — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that your breastfed baby has occasional frothy stools but is feeding well and gaining weight normally — 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 foamy, watery stools are very frequent and your baby shows signs of dehydration such as fewer wet diapers, no tears, dry mouth, or 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 baby foamy or frothy poop normal?
When should I call the doctor about baby foamy or frothy poop?
When is baby foamy or frothy poop normal?
What causes baby foamy or frothy poop?
What should I mention to my pediatrician about baby foamy or frothy poop?
Is baby foamy or frothy poop normal at 0-3 months?
Is baby foamy or frothy poop normal at 3-6 months?
Should I go to the ER for baby foamy or frothy poop?
Does baby foamy or frothy poop go away on its own?
References
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Baby Foamy or Frothy Poop.
Things to mention
- Describe when you first noticed baby foamy or frothy poop and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if your breastfed baby consistently has foamy green stools and seems fussy or uncomfortable during feeds.
- Mention if foamy stools are accompanied by poor weight gain or slow growth.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- Your breastfed baby consistently has foamy green stools and seems fussy or uncomfortable during feeds
- Foamy stools are accompanied by poor weight gain or slow growth
- Your baby has foamy, mucusy stools that persist for more than a week
Urgent signs to report immediately
- Foamy, watery stools are very frequent and your baby shows signs of dehydration such as fewer wet diapers, no tears, dry mouth, or lethargy
- Foamy stools contain blood or significant mucus along with fever or vomiting
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 foamy or frothy poop are normal. Talk to your pediatrician if foamy, watery stools are very frequent and your baby shows signs of dehydration such as fewer wet diapers, no tears, dry mouth, or 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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