Loose Stools in School-Age Children: What It Means When Tests Are Normal

Written and clinically reviewed by Bahee Van de Bor, RD, BCAPSc PGDipDiet, Specialist Paediatric Dietitian, former specialist dietitian at Great Ormond Street Hospital, with over 20 years of clinical experience in paediatric digestive health.

The tests came back clear.

You were told there was nothing wrong.

And your child is still running to the toilet.

And the call comes back:

This article is about loose stools that have carried on, or kept coming back, over at least two months.

Diarrhoea that started in the last week or two is a different question, and needs looking at differently, particularly if your child is unwell or you are worried about dehydration.

It is written with primary school age in mind, roughly five to twelve.

If your child is under five, toddler diarrhoea is the more likely picture and there is a separate guide for that.

Why loose stools can continue when initial tests are normal

Let me tell you what those tests were actually looking at, because they were not all looking for the same thing.

Coeliac serology looks for antibodies associated with coeliac disease.

Faecal calprotectin helps identify inflammation in the bowel.

A stool sample may look for an infection that has not cleared.

Three different questions, three different answers.

Normal results can make those particular conditions less likely, depending on which tests were done and the circumstances they were done in.

Rome V says that in most cases the likelihood of underlying organic disease can be reasonably excluded through basic bloodwork and stool tests, which is genuinely reassuring and worth holding onto.

But here is the part nobody explains at the appointment.

None of those tests diagnoses or rules out functional diarrhoea or IBS.

Those are positive diagnoses, made on the overall pattern of symptoms after proper assessment.

They are not what is left over when the tests come back empty.

So a clear set of results is not the end of the conversation. It is the point at which a different one should start.

What functional diarrhoea means in an older child

Here is the bit that has genuinely changed, and most families have not been told.

Functional diarrhoea used to be treated as a young child’s condition. That is where the everyday term “toddler diarrhoea” comes from, and it carried an unspoken promise: they will grow out of it by about four.

The Rome V criteria, published in 2026, extended the diagnosis all the way up to 18 years.

The Committee did that because studies kept describing it in school-age children and adolescents. It was there all along.

So a nine-year-old with frequent loose stools is not a toddler who failed to grow out of something. She may now meet the criteria for a recognised diagnosis, one that affects roughly 2 in 100 children.

What a clinician is actually checking

For a child aged four or over, Rome V asks for all of the following:

• More than two bowel movements a day on average, with at least a quarter of stools unformed. Bristol types 6 or 7.
• Onset somewhere between six months and 18 years of age.
• The picture does not meet the criteria for functional constipation, for IBS with diarrhoea, or for non-retentive faecal incontinence.
• After appropriate assessment, the diarrhoea is not fully explained by another medical condition.

And it must have been going on for at least two months.

Notice how much of that is about what it is not.

Two of the four criteria rule out competing diagnoses or other medical explanations.

That is why assessment comes first, and why a diagnosis cannot be arrived at from a symptom list, however good the list is.

Functional diarrhoea or IBS with diarrhoea? Pain is the dividing line

Now here comes the part that changes what you do next.

You have been asking, understandably, “what is wrong with my child?”

I would ask something different first.

Is tummy pain a significant part of this, or not?

That will not give you a diagnosis. But bring the answer to your appointment and it gives the clinician a useful place to start.

Rome V puts it plainly. Functional diarrhoea is characterised by diarrhoea without significant pain. IBS with diarrhoea has pain as the predominant symptom.

It also says the two can overlap, and that the clinician’s job is to work out which feature predominates. So it is not a clean line in every child, and it is not meant to be used as one.

What IBS with diarrhoea actually means

Most families arrive with the label already attached and nothing underneath it.

Someone said the word IBS, the tests were clear, and that was that.

So let me undo the most damaging idea in that whole encounter.

IBS is not what your child gets called when the tests find nothing.

It is a positive diagnosis, made on a specific pattern, in the same way a clinician diagnoses a migraine without scanning the brain.

Here is what Rome V asks for.

• Tummy pain on average at least four days a month, linked to going to the toilet, or to a change in how often your child goes, or to a change in how formed the stools are.
• Abdominal pain is the predominant symptom.
• In a young person who has started periods, the pain does not happen only during menstruation.
• After appropriate assessment, the symptoms are not fully explained by another medical condition.

And, as with functional diarrhoea, at least two months.

That second point does a lot of work and is often skipped. Pain has to be leading. If the loose stools are leading and the pain is occasional, that is a different picture.

The third point is new in Rome V. This qualification helps prevent bowel symptoms that occur only around menstruation being classified as IBS without considering menstrual or gynaecological causes.

IBS-D is the subtype where loose or watery stools predominate.

Clinicians use the pattern of abnormal stool forms on the Bristol Stool Chart to distinguish IBS-D from constipation-predominant or mixed IBS.

If you want to check which type you are looking at, the poo chart post walks through all seven.

What it tends to look like at home

In clinic, the primary school picture is fairly consistent.

Pain that changes around opening their bowels. It may ease, it may worsen, or it may arrive at the same time.

Urgency, so the toilet has to be now.

A child who knows exactly where every toilet is between home and school.

Symptoms that are worse in term time than in the holidays, which parents often notice and then dismiss as coincidence.

And frequently, a child who has stopped mentioning it, because mentioning it has never once helped.

On the age of six

Rome V sets six as the minimum age for an IBS diagnosis, because no studies have described IBS in children younger than that.

I want to be clear about what that means, because it lands badly with parents of five-year-olds.

It is a gap in the evidence. It is not a ruling that your child cannot be suffering.

A five-year-old with these symptoms still needs assessing, and can still be helped. What they should not be given yet is the label.

Is it IBS if my child has no pain?

Probably not.

If loose stools are there and pain is not a significant feature, functional diarrhoea fits better, and it has its own criteria.

I am spelling this out because I regularly meet families who have been told “it’s probably IBS” about a child who is not in pain at all.

That matters, because the two may need quite different management.

Could the loose stools actually be constipation?

Yes, and this is one of the patterns I see catch families out most often.

When stool builds up and hardens, liquid stool from higher up can leak around the blockage and arrive looking exactly like diarrhoea. It is called overflow.

A child can go every single day and still be significantly constipated.

If your child has soiling or skid marks they do not seem to notice, a bloated or uncomfortable tummy, or stools that swing between nothing for days and then loose, read is my child’s diarrhoea actually constipation before changing anything about their diet.

It is worth getting this the right way round first, because some changes intended to treat diarrhoea can worsen underlying constipation.

Other reasons loose stools persist

A few other patterns turn up often enough to be worth ruling in or out.

After a stomach bug

If this started with a sickness bug and never resettled, that is a recognised pattern with its own mechanisms, and I have written about it properly here.

Fructose and sorbitol load

In older children this rarely looks like juice in a beaker. It looks like squash all day, a smoothie on the way to school, sugar-free gum, and the volume a growing child can get through without anyone counting.

Sorbitol in particular draws water into the bowel.

A gut that has turned its volume up

After illness, or alongside stress, the gut sends stronger signals than it used to, so ordinary digestion registers as urgent or uncomfortable.

The clinical term for this is visceral hypersensitivity, and it can happen even when a proper assessment has found nothing structurally wrong.

Needing the toilet straight after eating

That is the gastrocolic reflex, it happens in everyone, and in a sensitive gut it can fire much harder. If breakfast is the worst meal of the day in your house, start here.

Why cutting out dairy or gluten often does not help

By the time families reach me, dairy has usually gone.

Sometimes gluten too.

I understand exactly why. It is the one lever a parent can pull without waiting for an appointment, and doing something feels better than doing nothing.

Here is the problem.

If the driver is fast transit, or a sensitised gut, or a backlog of stool higher up, then removing dairy may not address the underlying cause.

The loose stools carry on, and now they carry on in a child eating a narrower diet.

On gluten specifically

There is one thing worth knowing before anyone takes gluten out.

Please don’t remove gluten until your child has finished coeliac testing.

Coeliac serology relies on your child eating gluten regularly.

Take it out first and the test can come back falsely reassuring.

Your child then has to go back on gluten and do the whole thing again, which is miserable for everyone.

And if symptoms did seem to settle when wheat came out, that does not establish gluten as the cause.

Fructans in wheat are FODMAPs, and taking bread and pasta out also changes fibre, portion sizes and often several other things in the same week. Any of those may be doing the work.

What the restriction costs

Narrowing a school-age child’s diet always costs something.

Calcium intake can drop unless you replace the dairy properly.

Packed lunches sadly becomes complicated.

So do birthday parties.

Sleepovers can also get stressful.

If something genuinely does need to come out, it should come out for a reason, for a set period, with a plan to put it back.

When I might recommend a reduced FODMAP trial

This one needs more care than it usually gets.

Rome V does say a low FODMAP diet may be trialled in older children with functional diarrhoea.

But the same chapter is candid that there are no randomised trials of treatment for functional diarrhoea in children at all, and that the recommendations rest on expert opinion and adult studies.

And for IBS specifically, the 2025 ESPGHAN and NASPGHAN guideline does not suggest a strict low FODMAP diet as a routine treatment for children, because there is very little evidence in children.

It also raises the burden of restrictive diets.

So I consider a reduced FODMAP trial selectively, and mainly for an older child with functional diarrhoea.

It is not an automatic next step for every child with IBS-D, and the evidence in children remains limited.

When we do use it, it runs in three phases.

Restriction, for four to six weeks at most. Long enough to see whether symptoms respond, and never intended as a long-term diet.

Reintroduction, testing the FODMAP groups back one at a time to find which ones your child actually reacts to.

Personalisation, eating as wide a diet as their gut will allow, permanently.

Reintroduction is the phase that actually helps your child.

It is also the phase families drop when they do this alone.

Staying in the restriction phase for months is not how the diet works, and it can carry nutritional, social and eating-related risks.

This is not a diet to start at home, and not one anyone should stay on.

What a proper assessment looks at

No symptom checklist can sort this out on its own.

A symptom diary can help reveal the pattern, but it still needs interpreting alongside growth, diet, medical history and the effect on daily life.

When I assess a school-age child with persistent loose stools, I am looking at:

• The stool pattern. Not just “loose”, but how often, what time of day, how formed, and whether it changes at weekends.
• The pain pattern, and how it sits around opening their bowels.
• What they actually eat and drink across a full week, including the drinks nobody counts.
• Growth, plotted, not guessed.
• What you have already tried, in what order, and what happened each time.
• Whether school has started to organise itself around the toilet.

That last one tells me more about the impact than any of the others, and no test measures it.

When persistent loose stools need a closer look

Why tummy pain is on that list

You may have noticed that pain appears twice in this article, and it looks contradictory. Earlier it pointed towards IBS with diarrhoea. Here it sits in the alarm list.

Rome V includes abdominal pain as an alarm feature when assessing possible functional diarrhoea, because uncomplicated functional diarrhoea should not involve significant pain.

Pain does not automatically mean your child has a serious condition.

It means the pattern may be IBS with diarrhoea, or something else, rather than straightforward functional diarrhoea. So it needs proper assessment rather than assuming.

The complete source list is Table 3 of the Rome V criteria, Alarm Features in Functional Diarrhea.

FAQ

Disclaimer 

This article is for educational purposes and does not replace individual medical advice. If your child exhibits red flag symptoms, such as blood in the stool, unexplained weight loss, or persistent fever, please consult your GP.