Constipation in children — why it happens, and how to treat it properly

About this guide

Constipation affects up to one child in three at some point, and it is one of the commonest reasons for a child’s tummy pain, poor appetite and, in some, soiling of underwear. Parents often try diet changes for months before seeking help, and treatment that is started is often stopped too early. Both mistakes prolong the problem.

This guide explains what is going on inside a constipated child, why the usual advice about fibre and water is only part of the answer, how treatment works, how long it takes, and the uncommon situations that need a doctor’s assessment early.

What is normal

Stool frequency varies enormously in healthy children:

• Breastfed babies may pass a soft stool after every feed, or once every few days, or occasionally once a week. If the stool is soft and the baby is feeding and growing, this is normal.
• Formula-fed babies usually pass stool at least once a day, and it is firmer.
• Toddlers and older children typically go between three times a day and once every two days.

Constipation is not about a number. It is about hard, painful or infrequent stools, and the effects that follow.

What constipation looks like

A child is likely to be constipated if two or more of these have been present for a few weeks:

• Fewer than three stools a week
• Hard, dry or pellet-like stools, or very large stools that block the toilet
• Pain or straining when passing stool, sometimes with a small streak of bright red blood from a tear at the anus (an anal fissure)
• Withholding behaviour: standing on tiptoe, crossing the legs, stiffening, hiding behind the sofa, “dancing” or clenching the buttocks. Parents often read this as trying to go. It is usually the opposite: trying not to.
• Soiling of underwear (see below)
• Tummy pain, bloating, poor appetite, irritability, and sometimes a return of daytime wetting or urinary infections because a full rectum presses on the bladder

In over 95% of children, no underlying disease is found. This is called functional constipation, and it almost always starts with a withholding cycle.

The withholding cycle

1. A child passes a hard or painful stool: after an illness, a change of diet, a period of poor drinking, or the start of toilet training.
2. The next time the urge comes, the child remembers the pain and holds on.
3. Stool held in the rectum has more water absorbed from it and becomes harder and larger.
4. The next stool hurts more, so the child holds on harder.
5. Over weeks, the rectum stretches to hold the backlog, becomes less sensitive, and the child stops feeling the urge at all.

By this stage the problem is physical, not behavioural, and no amount of encouragement will fix it until the backlog is cleared and the rectum has had months to shrink back to normal.

Common triggers: toilet training that started too early or too firmly, starting preschool or primary school (unfamiliar toilets, no time, embarrassment), a change to solids or to cow’s milk in infancy, illness with poor drinking, travel, and anxiety.

Soiling is not naughtiness

Many parents of constipated children are puzzled by a child who is “constipated” and yet leaves smears or soft stool in their underwear. This is overflow soiling: soft stool from higher up leaks around the hard mass in the stretched rectum, and the child genuinely cannot feel it or control it. It is a sign of significant constipation, not of laziness or defiance, and punishment makes it worse. It resolves when the constipation is treated properly.

When constipation needs a doctor’s assessment early

Functional constipation is common; the rare causes matter. Please see us promptly if:

• Constipation started in the first weeks of life, or your baby did not pass meconium within 48 hours of birth
• Your child is not growing or gaining weight as expected
• There is vomiting, especially green vomit, or a swollen, hard tummy
• Blood in the stool that is more than a small streak on the surface, or mixed in
• Stools are consistently very thin, like a ribbon
• There is weakness, numbness or altered walking, a dimple, tuft of hair or mark over the lower spine, or an abnormally placed anus
• Constipation began after starting a new medicine
• Your child has poor drinking, thirst and frequent urination, or other features that suggest an underlying condition such as an underactive thyroid or coeliac disease
• Your baby is under 12 months and constipated for more than a week or two despite simple measures

How treatment works

Treating functional constipation has three parts, and all three are needed. Diet alone rarely works once the withholding cycle is established.

1. Clear the backlog (disimpaction)

If there is a build-up of hard stool, it has to be cleared first. The usual treatment is a macrogol (polyethylene glycol) laxative, sold in Singapore as sachets or powder (Forlax, Movicol Paediatric and similar), dissolved in a drink. The dose is stepped up over a few days until the child passes soft, watery stool and the tummy is comfortable. Macrogol works by holding water in the stool; it is not absorbed, is not habit-forming, and is safe for long-term use in children.

Expect a few messy days. Warn your child, use pull-ups if needed, and do not stop when the first big stool appears.

Lactulose is an alternative for babies and for children who will not take macrogol; it is gentler and slower. Enemas and suppositories are not usually needed and should not be used at home without advice.

2. Keep stools soft for months (maintenance)

After disimpaction, a daily maintenance dose of macrogol keeps stools soft and painless so that the child stops holding on and the rectum recovers its normal size and sensation. This is the part most often cut short.

A useful rule: treatment continues for at least as long as the constipation has been present, and usually for several months after stools have become normal. Stopping as soon as things improve is the commonest reason constipation comes back. When the time comes, the dose is reduced gradually over weeks, not stopped suddenly.

The right dose is the one that produces a soft, easy stool most days; it is adjusted up or down according to the result, not fixed by age.

3. Build a toilet routine

• Sit on the toilet after meals, particularly after breakfast and dinner, for about 5 minutes. Eating triggers the bowel’s natural urge to empty. Keep it relaxed; no pressure to produce anything.
• Feet flat on a step or box so that the knees are higher than the hips. Dangling feet make it physically harder to push. A child-size toilet seat helps small children feel secure.
• Praise sitting, not just success. A simple sticker chart for sitting works well for younger children.
• Never punish accidents or soiling, and keep the toilet a calm, unhurried place.
• Talk to the school or preschool if your child avoids toilets there. Most are helpful once they understand.

Diet and drinks: helpful, not sufficient

• Fibre from fruit, vegetables, whole grains and legumes helps prevent constipation and supports maintenance. Fruits that help many children: papaya, prunes, pears, kiwi, dragon fruit and oranges. Whole-grain bread, brown rice, oats and beans add bulk.
• Fluids: enough water through the day, more in hot weather and with exercise. A child who is drinking normally does not need to be forced to drink extra.
• Cow’s milk: more than about 500 mL a day in a toddler fills the child up, crowds out fibre-containing food and is associated with constipation. Keep milk to a moderate amount and offer water with meals.
• Babies starting solids: pureed prunes, pears or papaya, and a little extra water, often help. Do not add sugar, honey or oil to bottles.
• Physical activity helps the bowel move.

What to expect

• Most children improve within days of disimpaction and the start of maintenance treatment.
• Soiling usually settles within weeks once stools are soft.
• Full recovery of rectal sensation and the habit of going regularly takes months. Relapses in the first year are common and are managed by stepping the dose back up promptly.
• A small number of children need longer treatment, or specialist input.

When to see a doctor

Come in if:

• Your child has had two or more of the signs above for more than a couple of weeks, or diet changes have not helped after a few weeks
• There is soiling, withholding behaviour, or painful stools with blood
• Tummy pain keeps returning, or your child has daytime wetting or urine infections alongside constipation
• Your child is on laxatives and things are not improving, or you are unsure how to adjust the dose
• Any of the early-assessment features above are present

How we manage constipation at our Punggol clinic

Children with constipation can be seen as walk-ins, Monday to Saturday, and can be booked online. Because a proper first assessment takes time, an extended consultation is worth booking if there is soiling, a long history, or several concerns.

• A careful history: when it started, what stools look like (the Bristol stool chart helps), withholding behaviour, soiling, toilet habits at home and at school, diet, growth and any red flags.
• Examination of the tummy, growth measurements and, where relevant, the lower back and anus. Internal examination is rarely needed, and tests such as X-rays are not routinely required.
• A written treatment plan: disimpaction dose schedule, maintenance dose, how to adjust it, and the toilet routine, so that everyone at home is doing the same thing.
• Follow-up at 2 to 4 weeks, then at intervals over the following months, to adjust the dose, keep the routine going and plan a gradual weaning at the right time.
• Referral to a paediatric gastroenterologist at KK Women’s and Children’s Hospital or another children’s service if there are red flags, or if constipation does not respond to properly used treatment.

Cross-links

• Vomiting and diarrhoea in children
• Fever in children
• Child & adolescent care: growth, development and everyday paediatric care at Punggol

Get in touch

Punggol: 658 Punggol East, #01-04, Singapore 820658 · Tel 6312 4589 · Walk-ins welcome Mon–Sat

Joo Chiat: 172 Joo Chiat Road, #01-01, Singapore 427443 · Tel 6920 1952 · By appointment

Email: admin@ktmc.sg

References

• National Institute for Health and Care Excellence (NICE). Constipation in children and young people: diagnosis and management. Clinical guideline CG99. 2010, updated 2017. nice.org.uk
• Tabbers MM, DiLorenzo C, Berger MY, et al. Evaluation and treatment of functional constipation in infants and children: evidence-based recommendations from ESPGHAN and NASPGHAN. J Pediatr Gastroenterol Nutr. 2014;58(2):258–274.
• Hyams JS, Di Lorenzo C, Saps M, et al. Functional disorders: children and adolescents (Rome IV). Gastroenterology. 2016;150:1456–1468.
• HealthHub, Ministry of Health Singapore. Constipation in children. healthhub.sg
• KK Women’s and Children’s Hospital (KKH). Constipation in children, patient information. kkh.com.sg
• Gordon M, MacDonald JK, Parker CE, Akobeng AK, Thomas AG. Osmotic and stimulant laxatives for the management of childhood constipation. Cochrane Database Syst Rev. 2016;(8):CD009118.

This information is for general education only and is not a substitute for medical advice. Laxative doses for children are individualised and adjusted to the result; please check with our team. v1.0 · September 2026 · Review due September 2028.