Constipation is the most common bowel problem in children. It is the inability to do a poo regularly or to completely empty the bowel.

It can start at any age (including babies) and affects up to 30% of all children. It’s particularly common among toddlers and pre-schoolers.

A child is constipated if they poo less than four times a week.

Constipation can be very uncomfortable and distressing for a child and difficult for the family to deal with.

How does the bowel work?

Diagram of the bowel

(Image: staff)

In order to explain why your child is having poo problems, it helps to understand how the bowel works. 

Food goes in

The food that we eat gets chewed into little pieces which are easy to swallow. When it enters the stomach, the food is mashed up even more and is turned into a soupy mixture. This then passes to the small bowel (or small intestine) where the nutrients are taken out and used by the rest of the body.

Waste is produced

The waste liquid - watery poo - then goes further down the digestive system to the large bowel (or large intestine). The large bowel has strong muscles which squeeze the poo along. The body absorbs water as the poo is squeezed along, so that it turns into a soft, smooth, sausage-shaped poo.

Poo reaches the rectum

When the poo reaches the rectum, the lowest part of the bowel, the rectum stretches and a message is sent to the brain saying you need to do a poo.

A child with a healthy bowel can pass soft poos (Type 4 on the Bristol Stool Form Scale) at regular intervals without pain or discomfort at least four times a week.

When things go wrong...

If a child doesn’t act on their body’s signal that they need to do a poo, maybe because they’ve experienced a painful poo in the past, poo can build up in the large bowel. The longer the poo stays there, the more water is absorbed, and the harder and bigger the poo gets.

If the poo stays in the rectum, the rectum stays stretched, and the ‘I need a poo!’ message is no longer sent to the brain. So your child might have no idea that they need to do a poo!


Meanwhile, more liquid poo from higher up the bowel can leak around the hard lumps of poo and might even leak out of the child’s bottom – this is called soiling or overflow. This poo might be runny, so you might think your child has diarrhoea, or it might be hard little bits, or both.

Early identification is important

It’s easy to miss the signs of constipation, so the condition is often left untreated, misdiagnosed, or not treated properly. It’s important to deal with constipation early to prevent the child from suffering unnecessarily and to stop it developing into a more serious problem possibly requiring treatment in hospital.

In England alone, there are 15,000 hospital admissions for paediatric cases of chronic constipation and urinary tract infections each year, 80% of which could be avoided, according to the National Institute for Health and Care Excellence (NICE).

For most children, constipation can be successfully treated. However, in some cases it can be a long and difficult journey; the child may need on-going support from health professionals and a lot of patience and encouragement from parents and carers.

Full size version of infographic (PDF file)

Follow this link to learn how to spot the signs of constipation.