What is Stomach Flu?

Think you might have stomach flu? Find out what stomach flu is and how can you prevent it.

Most of us know just how unpleasant stomach flu can be. Stomach cramps, nausea, vomiting and diarrhoea all combine to make this nasty viral infection, also known as gastroenteritis, memorable for all the wrong reasons.

But do you know what causes stomach flu, how it can be treated, and how to tell the difference between stomach flu and food poisoning? Read on to find out.

What is stomach flu?

Stomach flu, which your doctor will most likely refer to as gastroenteritis, is caused by a viral infection in the digestive system. This short-term infection causes inflammation of the stomach and the gastrointestinal tract, resulting in the discomfort of vomiting, watery diarrhoea and stomach cramps. Some of these symptoms give rise to a few of the more informal and colourful names for gastroenteritis, “the runs” and “the trots” being two examples.

Although it has flu in the name, stomach flu should not be confused with influenza, which is a completely separate problem. Viral gastroenteritis is caused by viruses such as norovirus, rotavirus and calicivirus, which occur most commonly in winter and spring. The virus is spread when you come into contact with surfaces contaminated with human faeces, which is why it’s essential to wash your hands thoroughly after going to the toilet and before eating food.

However, it’s worth pointing out that bouts of gastroenteritis can also be caused by food poisoning. Eating food contaminated with bacteria such as Salmonella, Campylobacter or E.coli can cause you to become ill hours or even weeks later, so maintaining high hygiene standards and eating food that has been properly prepared and handled are the best methods of defence against this type of gastro.

What are the symptoms of stomach flu?

The symptoms of stomach flu caused by a viral infection typically appear within two days of you coming into contact with the virus. They can include:

  • Nausea and vomiting
  • Diarrhoea
  • Stomach cramps and abdominal pain
  • Low-grade fever, headache and chills
  • Loss of appetite
  • Bloating
  • Generally feeling unwell, including fatigue and body aches

While these symptoms may only hang around for a few days, it’s still possible for you to spread the virus for up to 48 hours after all your symptoms have disappeared.

One of the most serious complications of gastroenteritis is the dehydration brought on by frequent vomiting and diarrhoea. It’s important to stay as hydrated as possible while battling stomach flu, but severe cases of dehydration require immediate medical attention.

How do I treat stomach flu?

Unfortunately, there’s no “silver bullet” option you can use to treat stomach flu or its symptoms; once you have gastroenteritis, all you can do is try to ride it out. But doing the following may help the process:

  • Sleep. Stomach flu can knock it out of you. Spend as much time in bed as possible and get plenty of rest.
  • Stay hydrated. Vomiting and diarrhoea cause your body to lose fluids and essential electrolytes. Consider consuming electrolyte-replenishing drinks like Gatorade or Powerade.
  • Introduce food slowly. Stomach flu reduces the appetite, so when you introduce food again keep it bland. Think toast, crackers, plain yoghurt, and bananas.
  • Avoid medications. Use medications sparingly, or avoid them completely if possible. You may be tempted to take anti-vomiting or anti-diarrhoea drugs to control your symptoms, but as these medications will keep the infection inside your body they should only be taken when prescribed by your doctor. In many cases, the old saying that “it’s better out than in” applies.

What is the difference between stomach flu and food poisoning?

Gastroenteritis can also be brought on by food poisoning. However, because stomach flu and food poisoning commonly produce a range of similar symptoms, it can sometimes be hard to tell the difference between the two conditions.

Food poisoning is more common than stomach flu and is a result of eating food contaminated with infectious bacteria or parasites. For example, you’re at risk of food poisoning if you drink contaminated water or unpasteurised beverages, eat contaminated or undercooked meat, or consume raw fish or oysters.

Symptoms of food poisoning usually present within two to six hours of eating the contaminated food and can include:

  • Abdominal pain (which can be severe in some cases)
  • Nausea and vomiting
  • Watery diarrhoea
  • Loss of appetite
  • Fever and chills
  • Fatigue and lethargy
  • Muscle aches and headache
  • Sweating
  • Bloody stool or vomit (in severe cases)

Just as with stomach flu, dehydration brought on by frequent vomiting and diarrhoea is usually the biggest risk associated with food poisoning. However, certain types of bacteria can lead to serious complications for unborn babies, while some strains of E.coli can cause kidney failure.

Did you know?

  • There are approximately 111 million episodes of rotavirus worldwide each year.
  • Rotavirus (one of the viruses that causes gastroenteritis) kills more than 500,000 children under 5 years of age worldwide each year. Over 80% of those deaths occur in developing countries.
  • In Australia, rotavirus gastroenteritis is responsible for almost 50% of paediatric hospital admissions.
  • Rotavirus previously caused more than 10,000 hospitalisations in Australia each year, but this figure has reduced by more than 70% since the oral rotavirus vaccine was included in the national immunisation program in 2007.
  • The “Sydney 2012” mutant strain of norovirus caused several major gastroenteritis outbreaks around the world in 2012/13.

Need hospital cover?

Content on this website is provided for education and information purposes only. Information about a therapy, service, product or treatment is not an endorsement and does not imply its appropriateness for your circumstances. Our information is not intended to replace advice from your doctor or other registered health professional and you should not rely on this general information for diagnosis or answers for your particular circumstances. Instead seek advice from a registered health care professional. This content has been prepared for Australian audiences and was accurate at the time of publication but, over time, the currency and completeness of the published material may change.

Picture: Shutterstock

Tim Falk

A freelance writer with a passion for the written word, Tim loves helping Australians find the right home loans and savings accounts. When he's not chained to a computer, Tim can usually be found exploring the great outdoors.

Was this content helpful to you? No  Yes

Related Posts

You might like these...

Ask an Expert

You are about to post a question on

  • Do not enter personal information (eg. surname, phone number, bank details) as your question will be made public
  • is a financial comparison and information service, not a bank or product provider
  • We cannot provide you with personal advice or recommendations
  • Your answer might already be waiting – check previous questions below to see if yours has already been asked

Finder only provides general advice and factual information, so consider your own circumstances, or seek advice before you decide to act on our content. By submitting a question, you're accepting our Privacy & Cookies Policy and Terms of Use, Disclaimer & Privacy Policy.
Ask a question
Go to site