Gastroenteritis (tummy bug) gives you diarrhoea and vomiting, and is usually caused by viral or bacterial infections.

With gastroenteritis, your stomach and intestines become irritated and inflamed.

Infants and young children, older people, and people with a weakened immune system are most at risk of getting a severe bout of gastroenteritis.

These illnesses can all result in gastroenteritis:

If you are concerned about gastroenteritis, call Healthline on 0800 611 116 or see your doctor or practice nurse.

Viral gastroenteritis is highly infectious, and large numbers of people can be affected in a short amount of time. It spreads very easily from person to person, by contact with the vomit or faeces (poo) of an infected person. This could be from shaking hands with someone who has been sick and has the virus on their hands, or from contaminated (unsafe) objects like door handles and cutlery, and food and drink.

People usually get bacterial gastroenteritis by eating or drinking food or water that is contaminated with the bacteria. Bacterial gastroenteritis is less easily passed from person to person, but large numbers of people may become affected from contaminated food or water.

The main symptoms are normally diarrhoea and vomiting.

Other symptoms can include:

  • stomach pain
  • cramping
  • fever
  • nausea
  • loss of appetite and
  • headaches

Depending on the cause, symptoms may appear within a few hours to a couple of weeks after infection. The illness can range from mild to severe. Symptoms usually last one or two days, but can occasionally last for up to 10 days.

Diarrhoea and vomiting can easily cause dehydration, where your body doesn’t have enough fluid to function properly. Signs of dehydration include dry skin/dry mouth, feeling lightheaded, and being really thirsty. Make sure you drink plenty of fluids if you experience these symptoms.

Most people with gastroenteritis recover within a few days without needing medical treatment, as long as they don’t become dehydrated. To prevent dehydration, drink plenty of water and other fluids. Clear fluids, such as water and diluted cordials are best. Ice blocks are a good way of getting fluids into children.

Some people with severe gastroenteritis caused by bacteria may be given antibiotics. Only the symptoms can be treated with viral gastroenteritis.

If you are concerned, call Healthline on 0800 611 116 or see your doctor or practice nurse.

To protect others people with gastroenteritis should stay home from day care, school or work until at least 48 hours after their symptoms have gone. It's also important to wash and dry your hands thoroughly, especially:

  • before eating or preparing food
  • after going to the toilet
  • when changing nappies
  • after contact with an infected person


Auckland Regional Public Health Service is notified of acute gastroenteritis in some cases – for example, where there is a known causative organism, suspected common source, or where the person is in a high-risk occupation, such as a food handler or an early childcare worker.

We then monitor the number of people who have the disease and give health professionals advice on how to reduce its spread in the community.


There are specific requirements for notifiable diseases in the Auckland region.

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Last updated 22.11.2022

For health advice call Healthline for free anytime on 0800 611 116
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