What is gastroenteritis?

Gastroenteritis (often called 'gastro') is a common infection that spreads easily and affects your stomach and intestines. It makes the lining of your digestive system swell. Gastro is often mild and causes vomiting, diarrhoea, stomach pains and nausea.

Older people, young children and those with a weakened immune system are more likely to have severe symptoms.

What are the symptoms of gastroenteritis?

If you have gastro, you may have some of these symptoms:

• nausea and vomiting
• diarrhoea
• stomach pains and cramping
• fever, body aches, weakness, tiredness
• headaches
• loss of appetite

Vomiting usually lasts 1 to 2 days. Diarrhoea usually lasts around 1 to 3 days but can last up to 10 days.

If you have severe gastro, you may:

• not be able to keep down any fluids
• pass less urine (wee)
• feel dizzy when you stand up

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

What causes gastroenteritis?

Gastro may be caused by:

• viruses, which are the most common cause, including rotavirus and norovirus
• bacteria, like salmonella and campylobacter
• toxins produced by bacteria such as Clostridioides difficile
• parasites, like giardia and cryptosporidium

Viruses that cause gastro can be found in human faeces (poo) or vomit.

How does gastro spread?

Viruses can be spread:

• when you have contact with infected vomit or faeces (poo)
• through contaminated food, drinks or objects
• by person-to-person contact — coughing, sneezing or shaking hands with someone who is sick and has virus on their hands

Some bacteria and parasites that cause gastro are found in contaminated food or water — this is sometimes called 'food poisoning'. Food poisoning symptoms usually begin 6 to 12 hours after eating spoiled food.

How does C.diff cause gastro?

Gastro caused by Clostridioides difficile (often called 'C. diff') can happen after taking antibiotics. C. diff lives in the gut of many people in small amounts and doesn't cause any problems. Taking antibiotics can lead to an imbalance in your gut bacteria, allowing C. diff to grow more than usual and cause symptoms. Clostridioides difficile used to be called Clostridium difficile.

Read more on gut health.

Should I keep my child home from school when they have gastro?

Here's a list of common childhood illnesses, including gastroenteritis, and their recommended exclusion periods.

When should I see my doctor?

Adults and older children

You should see your doctor if you have:

• abdominal (tummy) pain that is getting worse
• frequent vomiting or diarrhoea
• blood or mucus in your poo
• a fever
• signs of dehydration, like passing little or no urine, urine that is dark or smelly or feeling faint or dizzy when standing
• other symptoms that worry you

Young children

Your young child should see a doctor if they:

• are less than 6 months old
• are less than 3 years old and have a fever over 38℃
• weigh less than 8 kg
• were born prematurely, or have other health problems
• pass blood in their poo, have dark green vomit or have severe stomach pains
• are unable to keep food or fluids down without vomiting
• are not getting better, or you are worried

You should also take your child to a doctor if they show signs of severe dehydration, like:

• being very sleepy or drowsy
• being very thirsty
• having less than 4 wet nappies a day
• having cold hands and feet
• having dry lips and tongue
• having sunken eyes and/or fontanelle
• having fast breathing

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

How is gastroenteritis diagnosed?

Your doctor can diagnose gastro by examining you and asking about your symptoms. If you're not getting better, your doctor may suggest a stool (poo) test to check what is making you sick.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

How is gastroenteritis treated?

Self-care at home

Most people recover from gastro on their own without needing treatment from a doctor. The main treatment is to drink plenty of fluids to avoid getting dehydrated.

Tips to manage gastro symptoms:

• Make sure you drink enough fluids so you don't get dehydrated. Sip clear fluids every 5 to 10 minutes. These help replace fluids lost from vomiting and diarrhoea. Try not to drink sugary drinks because they can make diarrhoea worse.
• Eat if you feel hungry. Start with simple foods such as crackers, rice, clear soup, a banana or dry toast.
• Rest as much as you can.
• Continue breastfeeding as normal.
• Talk to your doctor before taking anti-nausea or anti-diarrhoea medicines. Do not give anti-diarrhoea medicines to children.

Other treatment options

If your gastro is caused by bacteria or parasites, your doctor might prescribe antibiotics. Viral gastroenteritis does not need antibiotics. Read more on the differences between bacterial and viral infections.

If you become severely dehydrated, you may need fluids in an intravenous drip.

What are the complications of gastroenteritis?

Dehydration is the main complication caused by gastroenteritis. In babies, children and older people it happens more often.

Babies and children with gastro

The most common and serious complication of gastro in babies and children is dehydration. Children with health problems can get dehydrated faster.

If your baby is under 6 months, take them to a doctor if you think they have gastro. If they are older, it is still a good idea for them to be checked in case they are dehydrated.

• Babies — If you are breastfeeding your baby it's important to continue. Your baby may need to feed more frequently. You can also give rehydration fluid between feeds, if your baby needs to drink more. If you are using formula to feeding your baby, give them the usual amount, and then give them rehydration fluids if they're still thirsty.
• Children — it's important for your child to stay hydrated. If you can't find rehydration fluids, or your child refuses to drink them, you can try diluted fruit juice (1 part juice to 4 parts of water). You can also try giving a cube of ice, jelly, slushies, or using a medicine syringe (without a needle) to put water into their mouth.

Many medicines that adults take to stop vomiting or diarrhoea can be dangerous for babies. Before giving your baby or young child any medicine, be sure to ask your doctor or pharmacist.

Older people with gastro

Older people are more likely to have complications from gastro. They are at a higher risk of becoming severely dehydrated, and are more likely to need an intravenous (IV) fluid drip to replace fluids lost from diarrhoea or vomiting.

Gastro outbreaks are common in aged care facilities. Older people may also experience symptoms that mimic (look like) gastro, such as those caused by chronic bowel disease or by taking certain medicines.

Can gastroenteritis be prevented?

You can reduce the chance of spreading gastro by following these tips:

• If you have been sick with gastro and work in health care, residential or aged care or the food industry, do not go to work until 48 hours after your last episode of vomiting or diarrhoea.
• Wash and dry your hands after using the bathroom, changing nappies, cleaning up vomit or diarrhoea and before eating or preparing food.
• Wash clothing or bedding contaminated with vomit or diarrhoea using detergent and hot water.
• Clean bathrooms and toilets often.
• Don't share your towels, face cloth, toothbrush, cups, glasses or cutlery.
• Don't prepare or handle food for other people when you are sick.

If you think your illness was caused by food, report it to your local council's health department. Keep leftovers for testing.

Tips to reduce your chance of catching gastro:

• Avoid contact with people with gastro.
• Store and cook foods according to health regulations.
• Take care when handling animals and their faeces (poo) and urine (wee).
• Keep raw and cooked foods separate and make sure to cook them properly.

If you are travelling to places with poor hygiene or where the local tap water is not safe to drink, here are some tips:

• Only use bottled water for drinking and brushing your teeth.
• Don't put ice in drinks.
• Eat fruit you can peel yourself.
• Avoid uncooked foods, including salads.

Children and vaccination for rotavirus

Rotavirus is a virus that causes severe gastroenteritis in babies and young children. All young children are recommended to get the rotavirus vaccine at 2 months and 4 months. A third dose at 6 months of age may be needed.

This vaccine is effective in preventing rotavirus infection in about 7 out of 10 vaccinated children. Read more on immunisation and vaccinations for your child.

Resources and support

Read the Sydney Children's Hospital factsheets on gastroenteritis in children — factsheets are also available in languages other than English.

Visit the GESA (Gastroenterological Society of Australia) website, where you can find more information on gastro in kids.

For tips about staying hydrated, see drinking water and your health.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.

Languages other than English

The Victorian Department of Health has developed fact sheets about gastroenteritis in community languages.