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Constipation in Children

Jul 15, 2024 20 min readBy Entegro Health

Almost every child gets constipated at some point. What turns a rough week into a months-long problem is usually not the food on their plate. It is that going to the toilet started to hurt — and a small person made a very reasonable decision about that.

A parent serving breakfast to a young child at a bright family kitchen table

Constipation is one of the most common reasons children end up in a pediatric gastroenterology clinic. A meta-analysis of 37 population studies put the pooled worldwide prevalence of functional constipation in children at 9.5% (95% CI 7.5–12.1), with individual studies ranging from 0.5% all the way to 32.2%¹. “Functional” means there is no underlying disease driving it — which is the case for the overwhelming majority of children, and which is genuinely reassuring news.

It is also, unfortunately, the kind of problem that rewards early attention and punishes waiting. So this article does something a little unusual for a supplement company’s blog: it tells you what the guidelines actually say, including the parts where the answer is a prescription rather than a purchase.

What constipation actually looks like in a child

The obvious signs are the ones most parents already spot:

Fewer bowel movements than usual — the clinical criteria use two or fewer in the toilet per week²
Hard, dry or pellet-like stools, or occasionally enormous ones that genuinely block the toilet
Pain or straining when passing a stool
Tummy aches and cramps, a bloated-feeling belly, extra gas
Going off food, being unusually fussy or irritable

Then there are the two signs parents almost universally misread, and they are the ones that matter most.

Retentive posturing

A child who is trying not to go does not sit quietly on the toilet. They go rigid. They stand on tiptoe, cross their legs, clench, arch their back, hide behind the sofa, or squat and go very still with a look of enormous concentration. From the outside this looks exactly like a child straining to push. It is the opposite: it is a child holding on with everything they have. It is a formal diagnostic criterion for constipation², and mistaking it for effort is the single most common way this gets missed at home.

Overflow soiling

When a hard mass sits in the rectum for long enough, softer stool tracks around it and leaks out. Parents see skid marks or what looks like diarrhea in a child who has not properly gone in a week, and reasonably conclude the opposite of what is happening. Worse, it often gets read as laziness or regression. It is neither. It is a mechanical consequence of the blockage, and the international treatment guideline specifically lists explaining it to families as a matter of good clinical practice³.

One line worth remembering

In a child, consistency and pain tell you more than the number on the calendar. A child who goes every third day without fuss is fine. A child who goes daily but screams and passes rocks is not.

When to stop reading and call a doctor

Most childhood constipation is functional and not dangerous. But a short list of features points towards something else, and these need a clinician rather than a bit of extra fruit. They come from the red-flag tables in the pediatric literature² and from the UK NICE guideline on constipation in children⁴.

Get medical advice if any of these apply

Blood in the stool. Sometimes this is just a small tear from passing something hard, but it is on the red-flag list and it is not something to assess at home
Constipation that started at birth or in the first few weeks of life
Meconium that was late — more than 48 hours after birth in a term baby — or a family history of Hirschsprung disease
Ribbon-like stools, particularly in a baby under one
A swollen, distended tummy, especially with vomiting, or any green or bile-stained vomit
Weight loss, or growth that has stalled
Leg weakness, delayed walking, or anything unusual over the lower spine — a dimple, a tuft of hair, a birthmark or a lump
Severe pain, fever, or a child who seems genuinely unwell
Any constipation in a baby under one year, which deserves a proper look rather than home management

None of these mean something is definitely wrong. They mean a professional should be the one deciding.

A parent and child sitting together on a sofa in daylight, talking

There is one more reason not to wait, and it is the least intuitive part of this whole subject. The pediatric literature lists a set of factors that predict a worse long-term outcome, and two of them are simply how long the symptoms went on before anyone was told, and constipation during the first year of life². Delay is not neutral here. It is on the list.

The withholding cycle, which is the actual mechanism

If you take one thing from this article, take this. The dominant driver of constipation in young children is not fiber. It is stool withholding, and it accounts for the picture in somewhere between 80% and 100% of young children with functional constipation. More than 80% of those children specifically refuse to go in the toilet².

The review that reports those numbers describes the mechanism about as plainly as it can be put:

“Faulty toilet training and painful defecation due to passage of hard and large fecal masses lead children to withhold stools. The rectal mucosa, which is designed to absorb water in stools, absorbs water in feces, and the fecal mass in the rectum becomes rock hard and difficult to evacuate. Occasional passage of the fecal mass causes pain in the perianal region, which further aggravates withholding.”²

So the loop runs like this. One painful bowel movement — often from a small tear, or a stool that was simply too big — teaches the child that this hurts. The child holds on. The rectum does what it is designed to do and pulls water out of what is sitting there, so the next stool is harder than the last one. That one hurts more. The child holds on harder.

Every day of waiting makes the next attempt more frightening, not less.

Left alone for long enough, the rectal wall stretches to accommodate the growing mass, sometimes to the point of a megarectum, and a stretched rectum loses some of the contractility it needs to push anything out at all². This is why the problem so often looks like it appeared out of nowhere in a child who was previously fine, and why “more prunes” does not touch it once the cycle is properly established.

It is also why the fear is the real target. A child locked in this loop is not being difficult. They have learned something true — that this hurts — and they are acting on it sensibly. The job is to make it stop hurting for long enough that they unlearn it.

A parent and toddler reading a picture book together outdoors on a blanket

What sets it off

Once you understand withholding, the usual list of causes reads differently. Most of them are not direct causes at all — they are things that produce one uncomfortable bowel movement, which is all it takes to start the loop.

A painful bowel movement or a small anal tear. The usual trigger, and the one most often missed
Toilet training. Poor or rushed toilet training is a major risk factor in toddlers; the pediatric literature suggests starting somewhere between 18 and 30 months²
Dietary change, particularly the move to solid food, and a diet consistently low in fiber²
Changes in routine — travel, starting daycare or school, a new house, anything that disrupts the daily rhythm or makes the available toilet feel unusable
Stress and difficult life events, which show up in the epidemiology as well as the clinic^1,2
Cow’s milk protein allergy, which is a genuine contributor in some children⁵ — though a milk-free trial is a second-line move made with a clinician, not a DIY first step^2,3
Medications, worth mentioning to whoever you see
Underlying medical conditions — uncommon, but the reason the red-flag list above exists

Babies are a different problem

A lot of writing on this topic says “children and babies” and then describes school-age physiology. That is a mistake, because in the first year of life the picture is not the same — and the conditions that need excluding cluster precisely in that age group.

Straining is not the same as constipation

There is a specific, common, entirely benign thing infants do that looks alarming: a baby strains, goes red, screams for several minutes — and then passes a perfectly soft stool. This is infant dyschezia, defined in the Rome criteria as at least ten minutes of straining and crying before the successful passage of soft stools in an otherwise healthy infant under nine months^6,7. The baby simply has not yet worked out how to push and relax the pelvic floor at the same time. It resolves on its own. The soft stool is the tell.

The normal range is wider than people expect

A prospective cohort followed 1,052 healthy term infants weekly through the first seventeen weeks of life. Median defecation frequency was highest at three weeks — about four times a day — and drifted down to about twice a day by week seventeen, with a wide spread around those medians and a consistent difference between breastfed and formula-fed babies. Notably, hard stools were rare in both groups, at 1% or less⁸.

Which is the point. Counting days is a poor test in a baby. Whether the stool is soft, and whether the baby is feeding and growing, tells you far more.

For babies under one year, please see a clinician

We are not going to give you a dose for an infant. Constipation in the first year of life is on the list of factors associated with a worse outcome², the conditions that need ruling out — Hirschsprung disease, anal abnormalities, cow’s milk protein allergy, thyroid problems, spinal anomalies — are concentrated in this age group^2,4, and one narrative review of infant constipation concludes that while adding pro-, pre- or synbiotics to infant formula lowers the prevalence of constipation, “their efficacy in constipated infants is disappointing.”⁹

Separately: the FDA issued a safety communication in September 2023 about the risk of invasive disease in preterm infants given probiotic products, following a preterm infant who developed sepsis and died¹⁰. Probiotics of any brand are not appropriate for preterm infants, for children who are immunocompromised or critically ill, for children with central venous lines, or for children with short bowel or a damaged gut lining, outside of medical supervision.

What treatment actually looks like

ESPGHAN and NASPGHAN — the European and North American pediatric gastroenterology societies — published an updated joint treatment guideline in 2026. It reviewed 102 randomized controlled trials and graded everything using GRADE³. It is the best available answer to “what should we actually do,” so here is what it says.

First, clear what is already there

If there is a hard mass sitting in the rectum, nothing else will work until it is gone. The guideline’s good practice statement is blunt about this: managing fecal impaction is “vital to ensure long-term therapeutic success with any maintenance therapy,” and high-dose polyethylene glycol or enemas can be used to do it³. This is a step that happens with a clinician.

Then keep stools soft, for longer than feels necessary

Polyethylene glycol — PEG, sometimes labeled macrogol — is the only treatment in the entire 2026 guideline that carries a strong recommendation³. NICE reaches the same conclusion, naming PEG 3350 with electrolytes as first-line for both disimpaction and maintenance⁴.

The reason maintenance runs for months rather than days is the withholding cycle again. Children are kept on laxatives for at least two months² — not because the blockage takes that long to clear, but because the child needs a long enough run of painless, unremarkable bowel movements to stop being afraid of them. Stopping the moment things improve is how families end up back at the start.

And work on the toilet habit

The 2026 guideline recommends demystification, explanation and toilet training as good practice, and specifically that families be taught about withholding behavior and overflow incontinence³. The practical version: sit the child on the toilet for around five minutes after waking and after lunch and dinner, get the seating right so their feet are supported and their legs and perineum can relax, and reward the sitting rather than the result. One small counter-intuitive note from the same literature — handing over a phone or tablet as the reward for sitting is counterproductive².

And where do probiotics sit in that picture?

Honestly? Not in the treatment column. A 2022 Cochrane review of 14 randomized trials in 1,127 children found insufficient evidence to say whether probiotics help¹¹. A 2025 network meta-analysis pooling 41 trials found that probiotics “did not significantly increase the number of bowel movements per week when compared with any conventional treatment or placebo,” and concluded that mineral oil and PEG “should remain the first line of treatment”¹². The 2026 guideline found that when probiotic strains were pooled, no conclusion could be drawn against placebo at all³.

We sell a probiotic, so we will say this as clearly as we can: if your child is constipated, the thing to do is talk to a doctor, not to reach for a supplement — ours or anyone else’s.

Food, water and running around

This is the section where most articles overpromise, so a correction first. Both guideline sources say the same thing, and it is not what you would expect.

“There is no evidence to support physical activity, fluid, or fiber intake in the treatment of FC in children beyond the recommended daily amounts.”³

“Increasing water intake or hyperosmolar fluid has no significant effect on defecation frequency or improvement of consistency of stools.”²

NICE puts it even more directly: do not use dietary interventions alone as first-line treatment for idiopathic constipation⁴.

So the honest framing is this. Getting your child up to a normal, age-appropriate intake of fiber, fluid and daily movement is worth doing, and if they are falling short of it, fixing that is a sensible first step³. Pushing them beyond normal intake is not a treatment, and treating it as one mostly delays the thing that would work.

Fiber, with an actual number

A parent and toddler choosing fresh apples from a bowl of fruit in a kitchen

A usable target does exist: the American Health Foundation recommendation, cited in the pediatric literature, is the child’s age in years plus 5 to 10 grams of fiber per day for children over two². So roughly 11 to 16 grams for a six-year-old. Fruit, vegetables, beans and whole grains rather than a supplement.

On fiber as a treatment, the evidence is softer than the marketing suggests. A systematic review and meta-analysis of fiber in childhood constipation found some benefit but concluded that the variety of fiber types, study designs and small sample sizes made strong recommendations difficult¹³. Worth eating. Not a cure.

Fluid

A young girl drinking a glass of water beside a sunny kitchen window

Aim for the normal recommended amount for their age and stop there. The evidence that drinking extra water helps constipation in children is, per the two sources above, absent. That is not a reason to let a child get dehydrated — it is a reason not to turn water into a battleground while the actual problem goes untreated.

Movement

Three children running and laughing together outdoors on a sunny playground

Same story. Normal daily physical activity is part of the guideline’s general recommendation for a child with constipation³, and there is no evidence that going beyond it treats anything. Children should run around because running around is good. Not as a prescription.

Where Flourish fits

Nowhere in the paragraphs above, and we would rather say so than pretend otherwise.

Flourish is a daily living liquid probiotic for general gut health, for adults and for children from around one year old. It is not a treatment for constipation, and nothing in this article should be read that way.

A parent sitting on a bed with two smiling toddlers, one holding a bottle of Flourish

What is actually in it

Flourish Original and Flourish Junior each contain 11 live cultures spanning nine genera, including both bacteria and a beneficial yeast. Those are species-level identifications, not strain designations — which matters, because probiotic effects are strain-specific, and no strain’s published evidence transfers to a product that does not declare strains^3,14. It is one of the reasons we are not making claims here.

Flourish is a fermented liquid, bottled in the liquid it was fermented in rather than freeze-dried into a capsule, so it carries the metabolites of that fermentation along with the live cultures. That is a compositional statement about what a fermented liquid is, not a health claim — and it is worth being precise about a piece of terminology while we are here: short-chain fatty acids on their own are not postbiotics. The international consensus definition specifically excludes purified metabolites, naming SCFAs, and requires postbiotics to contain inanimate — killed — microorganisms¹⁵. A live product is, by definition, not a postbiotic. We have gone through that at more length in Flourish Probiotics and Postbiotics, and we would rather be consistent than convenient.

Giving it to a child

The practical advantage of a liquid is real and has nothing to do with any condition: there is no capsule to pry apart and no tablet to hide. It measures out with a spoon and the whole family can share a bottle.

One genuinely useful piece of timing advice, and it slightly contradicts the obvious approach. A laboratory model of the upper digestive tract found that survival of a probiotic was best when it was given with a meal or about thirty minutes before one, and that survival in milk or an oatmeal-and-milk mixture was significantly better than in apple juice or water¹⁶. So if you are mixing a dose into something, milk beats juice. Note that this was an in-vitro model of a capsule product rather than a study of Flourish, so treat it as a sensible default rather than a finding about this bottle.

Start small and build up, as with any new supplement, and if your child has a health condition or takes regular medication, ask their clinician before starting.

The short version

Constipation in children is common, usually functional, and usually driven by a cycle of pain and withholding rather than by anything on the plate. Retentive posturing and overflow soiling are the two signs most often misread. Blood in the stool, symptoms from birth, a distended belly with vomiting, faltering growth or any constipation in a baby under one all need a clinician. Polyethylene glycol is the guideline-recommended first-line treatment and there is no good substitute for it. Fiber, fluid and movement are worth getting up to normal levels and are not worth pushing past them. And waiting is not free — the longer it runs before anyone looks at it, the harder it is to unwind.

About this article

Written by: Kelsy Armstrong, Entegro Health | Originally published: July 2024

Important information

This article is for general education and isn’t a substitute for professional medical advice, diagnosis, or treatment. Nothing here diagnoses, treats, cures or prevents any condition. If your child is constipated, or if any of the features listed above apply, please speak to a qualified health professional.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Sources

Koppen, I. J. N., Vriesman, M. H., Saps, M., Rajindrajith, S., et al. (2018). Prevalence of functional defecation disorders in children: a systematic review and meta-analysis. The Journal of Pediatrics, 198, 121–130.e6 — 37 studies; reported prevalence of functional constipation ranged from 0.5% to 32.2%, with a pooled prevalence of 9.5% (95% CI 7.5–12.1); geographical location, dietary habits and exposure to stressful life events were associated with prevalence. Source
Rajindrajith, S., Devanarayana, N. M., & Benninga, M. A. (2022). Childhood constipation: current status, challenges, and future perspectives. World Journal of Clinical Pediatrics, 11(5), 385–404 — Table 1 sets out the Rome IV diagnostic criteria, including retentive posturing and two or fewer defecations in the toilet per week. “Stool withholding is the commonest pathophysiological mechanism for developing FC in young children”; 80%–100% of young children with functional constipation show withholding and more than 80% of withholders refuse to pass stools in the toilet. Table 4 lists red-flag features including blood in stools, delayed passage of meconium, ribbon-like stools, bilious vomiting and failure to thrive. Table 5 lists factors that negatively affect prognosis, including longer duration of symptoms before presentation and constipation during the first year of life. Maintenance laxatives for at least two months; toilet sitting for five minutes after waking and after lunch and dinner; phones or tablets as rewards while sitting are counterproductive. Fiber target of “age in years plus 5 g – 10 g” per day for children over 2. “Increasing water intake or hyperosmolar fluid has no significant effect on defecation frequency or improvement of consistency of stools.” Source
Gordon, M., de Geus, A., Boruta, M., Banasiuk, M., Benninga, M., Borrelli, O., et al. (2026). ESPGHAN/NASPGHAN guidelines for treatment of functional constipation in children aged 0–18 years. Journal of Pediatric Gastroenterology and Nutrition, 83(2), 335–366 — 102 randomized controlled trials, GRADE methodology. Polyethylene glycol is the only treatment carrying a strong recommendation. “When all probiotic strains were pooled in a meta-analysis, no conclusions could be drawn for probiotics compared to a placebo.” “There is no evidence to support physical activity, fluid, or fiber intake in the treatment of FC in children beyond the recommended daily amounts.” “Other pro- and synbiotic preparations do not have sufficient evidence at a strain level to support such recommendations.” Good practice statements cover management of fecal impaction and educating families about withholding behavior and overflow incontinence. Source
National Institute for Health and Care Excellence (NICE) clinical guideline CG99, Constipation in children and young people: diagnosis and management — red-flag features in history and examination; “Do not use dietary interventions alone as first-line treatment for idiopathic constipation”; polyethylene glycol 3350 with electrolytes as first-line for both disimpaction and maintenance. Source
Pensabene, L., Salvatore, S., D’Auria, E., Parisi, F., et al. (2018). Cow’s milk protein allergy in infancy: a risk factor for functional gastrointestinal disorders in children? Nutrients, 10(11), 1716. Source
Benninga, M. A., Faure, C., Hyman, P. E., St James Roberts, I., Schechter, N. L., & Nurko, S. (2016). Childhood functional gastrointestinal disorders: neonate/toddler. Gastroenterology, 150(6), 1443–1455.e2 — the Rome IV criteria for the 0–4 year age group, including infant dyschezia. Source
Kadim, M., Merendar, P. U., Hartono, G., et al. (2023). Prevalence, risk factors, and pediatrician awareness of infant dyschezia in Indonesia. Pediatric Gastroenterology, Hepatology & Nutrition, 26(2), 116–124 — states the criteria verbatim: “The current Rome criteria IV defines infant dyschezia as straining and crying for at least 10 minutes before successful passage of soft stools in an infant <9 months old without any other health problems.” Source
Solasaari, T., Korpela, K., Lommi, S., Hyvönen, S., et al. (2024). Bowel function in a prospective cohort of 1052 healthy term infants up to 4 months of age. European Journal of Pediatrics, 183(8), 3557–3565 — defecation frequency highest at 3 weeks (median 4/day, IQR 2.9–5), declining to a median of 2/day by week 17; breastfed infants defecated more often than formula-fed infants at every time point; hard stools were rare (1% or less). Source
Steurbaut, L., Levy, E. I., De Geyter, C., Buyse, S., et al. (2023). A narrative review on the diagnosis and management of constipation in infants. Expert Review of Gastroenterology & Hepatology, 17(8), 769–783 — “While the supplementation of infant formula with pro-, pre- and/or synbiotics decreases the prevalence of constipation, their efficacy in constipated infants is disappointing.” Source
US Food and Drug Administration (29 September 2023). Risk of invasive disease in preterm infants given probiotics formulated to contain live bacteria or yeast — safety communication issued after a preterm infant given a probiotic in hospital developed sepsis caused by Bifidobacterium longum and subsequently died; FDA has not approved any probiotic product for use as a drug or biological product in infants. Source
Wallace, C., Sinopoulou, V., Gordon, M., Akobeng, A. K., et al. (2022). Probiotics for treatment of chronic constipation in children. Cochrane Database of Systematic Reviews, 3(3), CD014257 — 14 randomized trials, 1,127 children; insufficient evidence to draw conclusions about efficacy, with heterogeneity too severe to pool defecation frequency. Source
Harris, R. G., Neale, E. P., & Batterham, M. (2025). Efficacy of probiotics compared with pharmacological treatments for maintenance therapy for functional constipation in children: a systematic review and network meta-analysis. Nutrition Reviews, 83(6), 1006–1034 — 41 trials pooled for defecation frequency. “Probiotics did not significantly increase the number of bowel movements per week when compared with any conventional treatment or placebo.” “Mineral oil and polyethylene glycol were the most effective treatments… and should remain the first line of treatment.” See also Wojtyniak, K., & Szajewska, H. (2017), European Journal of Pediatrics, 176(9), 1155–1162: “Limited evidence does not support the use of any of currently evaluated probiotics in the treatment of functional constipation in children.” Source
Piccoli de Mello, P., Eifer, D. A., & Daniel de Mello, E. (2018). Use of fibers in childhood constipation treatment: systematic review with meta-analysis. Jornal de Pediatria, 94(5), 460–470. Source
Zheng, J., Wittouck, S., Salvetti, E., Franz, C. M. A. P., et al. (2020). A taxonomic note on the genus Lactobacillus: description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae. International Journal of Systematic and Evolutionary Microbiology, 70(4), 2782–2858 — the reclassification underlying the genus count for the cultures in Flourish. Source
Salminen, S., Collado, M. C., Endo, A., Hill, C., Lebeer, S., Quigley, E. M. M., et al. (2021). The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Nature Reviews Gastroenterology & Hepatology, 18(9), 649–667 — a postbiotic is a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host”; the definition “would not include substantially purified metabolites in the absence of cellular biomass,” naming SCFAs among the excluded compounds. Source
Tompkins, T. A., Mainville, I., & Arcand, Y. (2011). The impact of meals on a probiotic during transit through a model of the human upper gastrointestinal tract. Beneficial Microbes, 2(4), 295–303 — an in-vitro model of the upper digestive tract using an encapsulated multi-strain product: “survival of all the bacteria in the product was best when given with a meal or 30 minutes before a meal… Survival in milk with 1% milk fat and oatmeal-milk gruel were significantly better than apple juice or spring water.” Source

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