By Dr. Anil Tambe
Pediatric Gastroenterologist & Hepatologist | Mumbai
Co-author, "Chronic Diarrhoea in Children", IAP Pediatric Practice Guidelines 2026
Most childhood diarrhoea is short-lived. A few loose motions, a couple of unsettled days, and the child is back to normal — usually a viral infection that needed nothing more than fluids and patience.
But some children don't follow that script. The motions continue past a week, past two weeks, and the family finds themselves on a third or fourth course of medicine with no clear answer. By the time they reach a specialist, the question has usually shifted from "how do we stop this?" to "why is it still happening?"
That second question is the right one — and it is the one this article is about.
Doctors use duration and onset to separate three different situations, and the distinction matters because it changes what we look for.
Acute diarrhoea: Comes on suddenly and settles within 14 days. The overwhelming majority is viral or bacterial infection, and it resolves on its own with adequate fluids.
Persistent diarrhoea: Also begins suddenly, but continues beyond 14 days. It is seen mostly in children under five and often follows an infection that has damaged the gut lining.
Chronic diarrhoea: Is different in character. It begins gradually, builds slowly, lasts beyond 14 days, and points towards an underlying cause — problems with absorption, inflammation of the bowel, or occasionally a condition present from birth.
The World Health Organization defines diarrhoea as passing unusually loose or watery stools at least three times a day. In children, consistency matters more than frequency. A breastfed infant may pass many soft stools each day and be entirely well. What counts is a change from that child's own normal.
Parents are often surprised at how much attention a gastroenterologist pays to a description of the stool. It is not squeamishness — the character of the stool is the single most useful pointer to what is going wrong, and it shapes every test that follows.
Broadly, four patterns point in four different directions.
Watery stools suggest a problem with absorption in the small bowel. This is the commonest pattern and includes lactose intolerance following an infection and damage to the gut lining from conditions such as coeliac disease.
Greasy, bulky, foul-smelling stools that are difficult to flush suggest fat is not being digested or absorbed. This points towards the pancreas or liver — conditions such as cystic fibrosis, pancreatic insufficiency, or cholestatic liver disease.
Stools with blood and mucus, often accompanied by urgency and cramping, suggest inflammation of the large bowel. Inflammatory bowel disease, certain infections, and allergic colitis in infants fall into this group.
Loose stools containing recognisable undigested food, in a child who is otherwise thriving and growing normally, usually indicate that food is simply moving through too quickly. This is toddler's diarrhoea — common, harmless, and frequently over-investigated.
Because these four patterns lead to entirely different investigations, describing the stool accurately saves a child from tests they never needed.
Most chronic diarrhoea has a treatable explanation. A smaller group carries features that should prompt a specialist assessment rather than another prescription.
Seek a pediatric gastroenterology opinion if your child has:
That last point deserves emphasis. Time spent cycling through medicines is time in which a child may not be growing properly — and in childhood, growth lost is not always fully recovered.
A common worry among parents is that investigation means an immediate battery of invasive tests. In practice, the opposite is true: a good evaluation is narrow and targeted.
History and examination come first, and do most of the work. The age at which symptoms began, the relationship to particular foods, recent infections or antibiotics, family history, and the child's growth chart together narrow the possibilities considerably before any test is ordered.
First-line tests are simple. Blood counts, inflammatory markers, protein and albumin levels, coeliac screening, and stool examination for infection and parasites answer the question in a large proportion of children.
Second-line tests are chosen, not routine. Depending on what the first round suggests, these may include stool tests for fat or pancreatic function, breath tests for carbohydrate malabsorption, imaging, or endoscopy with biopsies.
Genetic testing is reserved for a small group, mainly infants with diarrhoea from the first weeks of life.
Learn more about pediatric inflammatory bowel disease management .
The principle throughout is that tests should be tailor-made rather than one-size-fits-all. Ordering everything at once is expensive, stressful for the child, and often less informative than a sequenced approach.
Treatment follows the cause, and for many children it is entirely dietary.
Alongside the specific treatment, nutritional recovery is the priority. Children with chronic diarrhoea frequently arrive with deficiencies of iron, zinc, vitamin B12, or vitamin D. Correcting these deficiencies is part of getting the gut lining itself to heal.
Read more about pediatric nutrition management .
One thing to avoid: Medicines that slow the bowel are not recommended in children. Antibiotics have no role unless a specific infection has been identified — unnecessary courses can make matters worse.
Chronic diarrhoea sounds alarming, and for a family living through it, the exhaustion is real. But the outlook is genuinely good. Most causes are identifiable with straightforward tests, most are treatable, and many need nothing more than a dietary change supervised properly.
What makes the difference is not aggressive treatment. It is arriving at the right explanation early enough that a child's growth and nutrition are protected while it is being sorted out.
Beyond 14 days, diarrhoea should be evaluated rather than treated with another course of medicine. Seek help sooner if there is blood in the stool, weight loss, or signs of dehydration.
The diarrhoea itself is rarely the danger. The risk is nutritional — poor absorption over weeks to months affects weight, height, and micronutrient levels. This is why growth is monitored so closely.
Not without guidance. Lactose-free diets help in specific situations and for a defined period, but unnecessary or prolonged exclusion of milk can compromise nutrition.
If cow's milk protein allergy is suspected, the diagnosis needs a supervised elimination and a planned reintroduction to confirm it.
Evidence supports probiotics mainly for preventing antibiotic-associated diarrhoea. They are not an established treatment for chronic diarrhoea and are not a substitute for finding the cause.
Most children will not. Endoscopy is reserved for specific suspicions — inflammatory bowel disease, coeliac disease, and certain absorption disorders — where a biopsy is the only way to confirm the diagnosis.
When it is needed, it is a short procedure performed under anaesthesia by a paediatric gastroenterology team.
Learn more about pediatric endoscopy .
A thriving child with normal growth and no red flags most often has toddler's diarrhoea, which is harmless and typically improves with simple dietary adjustments — usually reducing fruit juice and ensuring adequate dietary fat.
It is still worth a review to confirm nothing is being missed.
The approach described here is set out in detail in the chapter on Chronic Diarrhoea in Children that I co-authored for the IAP Pediatric Practice Guidelines (Indian Academy of Pediatrics, Presidential Action Plan 2026).
It covers the pathophysiological classification, the tiered investigation pathway, aetiology-specific management, and a referral algorithm.
The chapter is freely available: Download from IAP India
If your child has had loose motions for more than two weeks, or you are concerned about growth, a specialist assessment can identify the cause and set the right treatment in motion.
Dr. Anil Tambe — Pediatric Gastroenterologist & Hepatologist, Mumbai
Dr. Anil Tambe is a Pediatric Gastroenterologist and Hepatologist in Mumbai and co-author of "Chronic Diarrhoea in Children" in the IAP Pediatric Practice Guidelines 2026.
Medical Disclaimer: This article is for general information and does not replace an individual medical consultation. Please consult a qualified doctor for advice regarding your child's health.