Vomiting and diarrhoea can be caused by highly contagious viral infections, and can spread through your family fast. It’s no fun for anyone.

The biggest risk associated with vomiting and diarrhoea is dehydration from losing a large amount of fluid and electrolytes. Dehydration can be alleviated by sipping on small amounts of an electrolyte solution like Hydralyte while you recover and get back on your feet.

You can recover faster by rehydrating with an electrolyte solution like Hydralyte.

What causes vomiting and diarrhoea?

Tummy bugs come in many shapes and forms.

There are viral infections like rotavirus and norovirus, which can spread like wildfire through child-care centres, aged-care facilities and hospitals. If your family is suffering through an outbreak of vomiting and diarrhoea, then it’s likely you’ve all got the same viral infection.

Viral pathogen Incubation period Average illness duration
A highly contagious virus, and the leading cause of acute gastroenteritis worldwide. Norovirus particles can live on surfaces for about three days, and in water for two weeks; and are resistant to many cleaning products.
18-48 hours 24-48 hours
A common cause of vomiting and diarrhoea, especially in young infants and children.
< 48 hours Up to 5 days


Then there are bacterial infections like E.coli and salmonella. Think of these as food poisoning – they are usually isolated to one unfortunate person. Just as nasty, but not likely to spread.

Bacterial pathogen Incubation period Average illness duration
Escherichia coli
E.coli is a common bacterial infection found in contaminated water or foods like raw vegetables and undercooked ground beef.
12 hours to 3 days 1 week
Salmonella spp.
A major public health problem in the developing world, transmitted by the ingestion of contaminated food. Salmonella particles can survive at -20C!
24-48 hours (up to 72 hours) Days to weeks depending on amount ingested
Shigella spp.
A bacterial infection that can cause severe vomiting and diarrhoea.
1-3 days 3 days
Campylobacter jejuni
A major cause of food poisoning in Australia.
1-7 days 1-7 days
Giardia duodenalis
Giardiasis is an infection in the bowel caused by a parasite. It is common amongst travellers to underdeveloped countries like Bali and India.
12-15 days Weeks to months


Some other conditions can cause vomiting and diarrhoea. Morning sickness, some medications and other stomach conditions can trigger an outbreak, leaving you feeling very depleted and dehydrated.

How to prevent the spread of viral infections

If one of your family members have been struck down with an infection that causes vomiting or diarrhoea. You should:

  • Wash your hands in soapy water after nappy changes and going to the toilet, and before food preparation or eating
  • Try to cover vomit (close the toilet lid immediately) to avoid the airborne spread of particles
  • Clean contaminated surfaces with detergent, warm water and bleach
  • Avoid vacuuming, as this can spread viral particles

If your child is vomiting or has diarrhoea, keep them home from childcare or school for a minimum of 48 hours, and avoid swimming pools for 14 days after the symptoms stop.

Monitoring your child

If your child is vomiting or has diarrhoea, then it’s very important to keep track of their fluid intake. Children (and the elderly) are more at risk.

It’s recommended that you keep a record of how much fluid your child is taking in, versus how often they are vomiting or going to the toilet. Make these observations every 15 minutes – the information will be useful for your doctor.

Top tip: offer your child the Hydralyte Electrolyte Ice Block to suck on.

Download our Oral Fluid Intake Chart

Rehydrating with Hydralyte

Hydralyte is scientifically formulated to contain the correct balance of glucose and electrolytes for rapid rehydration. The formulation is based on the World Health Organisation criteria for effective rehydration. Water alone, or sugary drinks are not as effective as Hydralyte, as they do not replace electrolytes which are lost during bouts of vomiting and diarrhoea


Age in years Electrolyte powder and Electrolyte solution Effervescent Electrolyte Tablets (recommended dose in first 6 hours)
Under 12 months 100mL / 90 mins 200-400mL
1-3 years 100mL / 90 mins 400-600mL
3-6 years 100mL / 60 mins 600-900mL
7-12 years 100mL / 30 mins 900-1500mL
Over 12 years 200mL / 30 mins 1200-2000mL


Continue to use Hydralyte while vomiting and/or diarrhoea persist and while symptoms of dehydration are present.

When can you eat food again?

Once you or your child is able to keep down significant fluids, you can gradually reintroduce solid foods. Avoid sweet, fatty and spicy foods – instead, try things like rice, potatoes, bread, cooked cereals and dry biscuits.


Seek medical advice if vomiting or diarrhoea persists for more than:

  • 6 hours in infants under 6 months
  • 12 hours in children under 3 years
  • 24 hours in children aged 3-6 years
  • 48 hours in children over 6 years and adults