What is gastroenteritis?

Gastroenteritis (gastro) is an infection of the digestive system. It causes diarrhoea (runny, watery poo), vomiting or both.

Gastro is a common illness that is infectious and easily spread between people.

It’s more serious in babies and small children, as they are more likely to become dehydrated.

What are the symptoms of gastroenteritis in babies?

If your baby has gastroenteritis, they may:

• vomit (often before diarrhoea begins)
• have diarrhoea, which can last up to 10 days
• have some abdominal (tummy) pain
• have a fever (a temperature over 38°C)

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

Read more about common signs of childhood illness.

What causes gastroenteritis in babies?

Gastro is often caused by viruses such as rotavirus or norovirus. Rotavirus is the most common cause of severe gastroenteritis in young children.

Less often, gastro is caused by bacteria (such as E. coli or salmonella) or parasites (such as giardia).

When should I see my doctor?

If your baby is under 6 months old and has gastroenteritis, they need to be checked by a doctor.

Any baby with gastro should see a doctor if they:

• have a lot of diarrhoea (8 to 10 watery poos a day or 2 to 3 large poos a day)
• vomit often and can’t keep fluids down
• have a fever (a temperature above 38°C)
• have less than 4 wet nappies a day
• have any blood in their poo
• have green vomit

You should also take your baby with gastro to see a doctor if they:

• are small (weigh less than 8kg)
• were born prematurely
• have other chronic (long-term) conditions

See your doctor if your baby has signs of dehydration. If your baby has severe dehydration, they may:

• have dry lips and mouth
• have dark-coloured urine (wee)
• have fewer wet nappies
• have cold hands and feet
• be more sleepy than usual

Severely dehydrated babies may also have a sunken fontanelle (soft spot) on their head.

Take your baby back to see your doctor if their symptoms are getting worse.

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How is gastroenteritis in babies diagnosed?

Your doctor will examine your baby and ask you about their symptoms. Gastroenteritis can usually be diagnosed based on symptoms alone.

Most infants with gastroenteritis do not need any tests. This is because the treatment for gastro doesn’t depend on what’s causing the infection.

If your baby has recently been overseas, your doctor may organise tests to exclude infections from the region of travel.

How is gastroenteritis in babies treated?

Treatment for gastroenteritis will depend on:

• how old your baby is
• how bad their symptoms are
• if they have any other health conditions
• whether they are dehydrated

Treating gastroenteritis at home

The main treatment for gastroenteritis is to make sure your baby keeps drinking enough. This helps to replace fluids lost due to diarrhoea and vomiting, and stops your baby from becoming dehydrated.

Treatment for babies under 6 months of age

Babies under 6 months of age who have gastro should always be seen by a doctor.

Treatment for babies over 6 months of age

Treatment for babies over 6 months of age depends on how you usually feed them.

Breastfed babies should continue to be breastfed but should be fed more often. An oral rehydration solution or water may be offered in addition to breastfeeds.

Formula-fed babies may need to have both an oral rehydration solution and their formula at normal strength.

Give your baby small amounts of fluids often. They can usually tolerate this better than a lot of fluids at once.

You should keep giving fluids even if they are vomiting.

If your older baby refuses water or oral rehydration fluids, try giving them diluted apple juice.

Oral rehydration fluids

Oral rehydration fluids are specially made to replace fluids and salts in the body. There are different types of oral rehydration fluids:

• powder or concentrated liquid that you mix with water
• tablets that you dissolve in water
• ice blocks
• pre-made drinks

They also come in lots of different flavours. You can buy oral rehydration fluids at your local supermarket or pharmacy.

Medicines for gastroenteritis in babies

Most babies do not need to take medicine for gastro. In fact, many medicines that stop vomiting or diarrhoea can be harmful for young children.

In most cases, your doctor will not prescribe antibiotics. This is because most gastro infections are caused by viruses. Viruses do not respond to antibiotic treatment.

Talk with your doctor or pharmacist about how best to treat your baby for gastroenteritis.

Other treatment options

If your baby is very dehydrated, they may need to be admitted to hospital. They may need fluids through a nasogastric tube (a tube from their nose into their stomach) or an intravenous drip (IV) directly into a vein.

What are the complications of gastroenteritis?

Nappy rash

If your baby has diarrhoea, you can help prevent nappy rash by changing your baby’s nappy often and using a zinc-based cream on their bottom.

This will stop the diarrhoea from burning your baby’s skin.

Dehydration

Babies have a high chance of dehydration and must be watched carefully. You will know your baby is dehydrated if they:

• have dry lips and mouth
• have dark-coloured urine (wee)
• have fewer wet nappies
• have cold hands and feet
• are very sleepy

Electrolyte imbalance

Hypernatraemia (an imbalance of electrolyte or minerals in the body) is a complication of gastroenteritis. It’s most often seen in babies less than one year of age.

Can gastroenteritis in babies be prevented?

Gastroenteritis is highly infectious. Wash your hands with soap and water before eating, before preparing meals and after changing dirty nappies.

Keep your baby away from other children until there has been no diarrhoea or vomiting for at least 24 hours. This includes keeping them home from childcare.

Your baby can be vaccinated against rotavirus infection. Australia’s National Immunisation Program Schedule recommends babies get this vaccination at the age of 2 and 4 months.

Resources and support

The Royal Children’s Hospital Melbourne has fact sheets on gastroenteritis in English and languages other than English.

Sydney Children’s Hospitals Network also has fact sheets on gastroenteritis in Chinese, Italian and Greek.