What is gastroenteritis?

Gastroenteritis is a general term for diarrhoea and vomiting triggered by an infection and inflammation of the digestive system (gut). There are many causes of gastroenteritis, including viruses (e.g. Norovirus, Rotavirus, Adenovirus); bacteria (e.g. Salmonella, Campylobacter); bacterial toxins (e.g. Staphylococcal food poisoning); parasites (e.g. Giardia, Cryptosporidium), chemicals and medications (e.g. some antibiotics). The exact cause of gastroenteritis can only be diagnosed by laboratory tests of faecal (poo) specimens.

What are the signs and symptoms of the illness?

Typical symptoms include diarrhoea and vomiting. Stomach cramps, fever and nausea may also be present.

What is diarrhoea?

Diarrhoea occurs when something upsets the normal process of your gut and so speeds up the whole digestive process. This makes you pass faeces (poo) more frequently than normal and the faeces are usually loose or watery in consistency. Normal bowel habits can vary with each person and this can be anything from 3 bowel movements per day to 3 per week. Normally, faeces should be solid but moist and easy to pass.

Diarrhoea usually lasts a day or two and usually comes on suddenly (acute attack). However, you can also have chronic diarrhoea, which lasts over a long period of time (2-3 weeks or months). Chronic diarrhoea may signal the presence of an underlying health problem and medical advice should be sought.

What is vomiting?

Vomiting (‘throwing up’) occurs when the brain receives certain information (e.g. food irritation or infection of the gut, motion from the inner ear) which causes the abdominal wall to contract and force out the contents of the stomach. Vomiting is usually harmless and often stops by itself.

Vomiting is more common in infants and children and can be triggered easily by overfeeding and motion as well as by gastroenteritis. Medical advice should be sought if someone is suffering from persistent vomiting or vomiting associated with a high fever or diarrhoea.

How bad is it?

Gastroenteritis is usually not serious and most people recover quickly. However, sometimes people are unable to drink enough fluids to replace those lost from vomiting and diarrhoea. These people can become dehydrated and may require medical attention. This is especially important for children, the elderly or those suffering from weakened immune systems.

Medical attention should be sought as soon as possible if the ill person:

  • Is a baby less than 6 months old

  • Is not drinking or has difficulty keeping fluids down

  • Is not urinating (‘passing wee’) or passing less urine than usual

  • Has dry lips and mouth and/or cold hands and feet

  • Is unusually lethargic, drowsy or irritable

  • Keeps vomiting or passing lots of diarrhoea

  • Has blood or mucus in their faeces (poo)

  • Has a high fever

  • Has unexpected symptoms (e.g. pain when passing urine, headache, ongoing stomach pains)

  • Has other health problems

  • Does not appear to be getting better (that is, not improving after 2 days)

Can the illness be spread?

Gastroenteritis caused by viruses, bacteria and parasites can be easily spread from person to person, especially if hygiene is poor, for example if someone who is ill prepares food for others without washing their hands. This is why it is important to thoroughly wash your hands with soap and water after using the toilet and before preparing, handling or eating foods.

Extra care must be taken when cleaning up faecal or vomit matter or items contaminated with these materials. Thoroughly clean and disinfect toilet and bathrooms areas after use.

Will I need time off school, childcare or work?

Your doctor, nurse or health protection officer can provide advice on this. Usually you can go back to work, childcare, school, etc., if you are well and have been free of symptoms for at least 48 hours. This is especially important if you are in a high-risk occupation such as a food handler, caregiver, nurse or childcare centre worker.

As you may be infectious for some days after recovery, good personal hygiene is important to prevent spreading the disease around. Good handwashing and hand drying after toileting is vital.

Contact your GP or Healthline (0800 611 116) for further advice.

For a printable version of this Gastroenteritis information, click here