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Diarrhoea: Causes

Acute diarrhoea

The most common cause of acute diarrhoea is infection. This can be spread in different ways:

  • from other people
  • food poisoning
  • contaminated water

Infection

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. These include the norovirus or 'winter vomiting' and rotavirus. All babies born in Ireland after 1 October 2016 are vaccinated against rotavirus.

Related topic

Baby and childhood vaccine information - HSE

Bacteria such as E. Colicampylobactersalmonellaand shigella can cause diarrhoea. Parasites like cryptosporidiumand giardiasiscan also cause diarrhoea.

Food poisoning

Germs in food can cause diarrhoea. Types of food poisoning can include salmonella, campylobacter, E coli and giardiasis. The HSPC websitehas more information about food poisoning.

Contaminated water

Drinking water contaminated with germs can make your child ill. These germs include E.Coli, cryptosporidium and 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. Private wells can become contaminated if not treated properly. Contact the Environmental Protection Agencyif you think your well water is contaminated.

Boil your water before using it if you think it might be contaminated

The Environmental Protection Agency has information on testing, treating and protecting private wells.

Chronic diarrhoea

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

Always bring your child to the GP if they have chronic diarrhoea that lasts more than 2 weeks

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 toddler's diarrhoea.

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

Other tips that might help:

  • do not offer your toddler fruit juices or squashes to drink
  • make sure your toddler has a good amount of fats in their diet like whole milk or yogurt
  • make sure they eat a healthy balanced diet with fruit and vegetables

Content supplied by the NHS and adapted for Ireland by the HSE.

Page last reviewed: 20/11/2018
Next review due: 20/11/2021