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Causes - Diarrhoea in babies and children

Diarrhoea is often caused by a stomach bug. Most children with diarrhoea can be cared for at home and will recover in a few days.

Acute diarrhoea

The most common cause of acute diarrhoea is infection.

This can be spread in different ways, such as:

  • from other people
  • food poisoning
  • contaminated water


Acute diarrhoea is most commonly caused by an infection, which can be passed from person to person.

Infections causing acute diarrhoea are most commonly caused by viruses. For example, the norovirus (the winter vomiting bug) and rotavirus.

All babies born in Ireland after 1 October 2016 are vaccinated against rotavirus.

Diarrhoea can also be caused by bacteria such as:

Parasites like cryptosporidium and giardiasis can also cause diarrhoea.

Cryptosporidiosis -

Food poisoning

Germs in contaminated food can cause diarrhoea.

Types of food poisoning include:

  • salmonella
  • campylobacter
  • e. coli
  • giardiasis

Contaminated water

Drinking water contaminated with germs can make your child ill.

Types of germs include:

  • e. coli
  • cryptosporidium
  • campylobacter

This is more common in countries where there is poor sanitation.

The public water supply in Ireland is treated with chemicals to kill germs. But private wells can become contaminated if they are not protected and treated.

If you think your well water is contaminated, contact the Environmental Protection Agency.

Contact the EPA -


If you think your water might be contaminated, boil it for drinking, cooking, preparing food, preparing formula and brushing your teeth.

Drinking water -

Chronic diarrhoea

Chronic diarrhoea is usually not caused by an infection. It's less common than acute diarrhoea and it may be a sign of an underlying health problem, such as:

Non-urgent advice: Take your child to see a GP, pharmacist or public health nurse if:

  • they have diarrhoea that lasts more than 7 to 10 days

Toddler’s diarrhoea

Toddler’s diarrhoea is a type of chronic diarrhoea that toddlers may get. It's not usually serious. Your child may feel well even if they have diarrhoea.

It is common to find undigested foods like peas and sweetcorn in a toddler's diarrhoea.

If you think your child has toddler's diarrhoea, make sure they are drinking enough fluids. Bring your child to a GP, who can make sure they are growing well.

Other tips that might help include:

  • not offering your toddler any fruit juices or squashes to drink
  • making sure they have a good amount of fats in their diet, like whole milk or yogurt
  • making sure they eat a healthy balanced diet with fruit and vegetables

Page last reviewed: 20 July 2023
Next review due: 20 July 2026