Last updated on 5 January 2022
What is gastroenteritis (stomach flu)?
Gastroenteritis is a viral infection which causes inflammation in your stomach and intestines. While it is also commonly known as a ‘stomach flu’ because it causes pain in the stomach area, it is not related to influenza at all.
It is a common condition, and anyone can be affected so read on to learn more about gastroenteritis symptoms, causes, treatment and prevention.
Gastroenteritis (stomach flu) symptoms
Most people experience gastroenteritis at some stage of their lives, so may have experienced some of these symptoms before:
In rare cases, gastroenteritis can leave you severely dehydrated. Watch out for:
- Intense thirst
- Sunken eyes
- Feeling foggy or unable to focus
- Blurred vision
- Dry mouth
Most people will recover without any complications, however those with underdeveloped or compromised immune systems, including infants and the elderly, it can be a dangerous illness.
When is gastroenteritis (stomach flu) an emergency?
If you experience these symptoms, visit the emergency department or call an ambulance. You should also seek help if:
- Your vomiting lasts more than a day
- Your diarrhoea lasts more than 2 days
- You have a chronic illness, such as diabetes, kidney disease or heart problems
- You notice blood in your vomit or stools
- You experience severe abdominal pain
- You have a fever of more than 38°C
- You are pregnant
Gastroenteritis (stomach flu) in children and infants
Children and infants are at particular risk of severe symptoms from gastroenteritis. Because they become dehydrated much faster than adults, keep a close eye on them if they are unwell. If you notice a sunken fontanelle (the soft spot on the top of their skull), extreme thirst, fewer or no wet nappies, dry skin, or severe irritability or lethargy, take them to the emergency room. If in doubt, seek medical attention.
Although gastroenteritis is not fully preventable, there are vaccinations available for some of the viral infections that cause it, such as rotavirus, which you should ask your doctor about.
Causes of gastroenteritis (stomach flu)
Gastroenteritis is a contagious viral infection, usually caused by rotavirus or norovirus. Norovirus is the most common cause of acute gastroenteritis worldwide, accounting for 685 million cases a year. Other viral infections leading to gastro include astrovirus and adenovirus.
Viral infections are easily spread which is why outbreaks of gastroenteritis are so frequent. The viruses that cause gastroenteritis are often transmitted through:
- Person to person contact
- Water or food that is contaminated
- Failure to keep surfaces clean
- Poor hand-washing techniques
- Being in cramped or close quarters with infected people
Is gastroenteritis (stomach flu) the same as food poisoning?
Contrary to popular belief, gastroenteritis is not the same as food poisoning. Gastroenteritis is the inflammation of the stomach or the intestine. However, if the gastroenteritis is caused by contaminated food, it is then labelled as food poisoning.
Food poisoning can be caused by food contaminated with bacteria, viruses or parasites. Most people find they contract food poisoning from the following:
- Raw eggs or meat
- Unpasteurised soft cheese or milk
- Raw fish or shellfish
- Leftover rice that was not reheated adequately
- Unwashed fruit or vegetables
The symptoms are the same as gastroenteritis. The onset of symptoms from eating the contaminated food varies, depending on the contaminant which can range from 1 hour to 7 days.
Preventing gastroenteritis (stomach flu)
- Wash your hands before cooking or handling food
- Sanitise surfaces, such as your kitchen counter or work desk, regularly
- Keep raw foods separate from ready-to-eat foods
- Avoid raw or undercooked food
- Refrigerate and freeze perishable food promptly
- Avoid close contact with infected individuals. If you are ill with gastroenteritis, you should avoid close contact with others until you feel better.
- Talk to your doctor about vaccinations for your child
Home remedies to treat gastroenteritis (stomach flu)
In most cases, gastroenteritis will resolve itself on its own. If the symptoms persist, or are severe, you may need a course of antibiotics. However, if the symptoms are mild, you can try the following home remedies for gastroenteritis treatment:
Increase your fluid intake
Do not drink too much at once in case it triggers vomiting. Try to take in a cup of water every hour. Young children should have a smaller amount every 30 minutes. Frozen ice popsicles are another way to encourage your child to take in fluid if they aren’t getting enough.
Encourage rehydration with electrolytes
Oral rehydration solutions can be dissolved in your water, or you can try sports drinks, which can help to replenish what minerals and fluids that your body has lost. Try to avoid sugary drinks if you can. Your doctor can advise what might be best for you and can offer you infant solutions if you have young children.
Eat easily digestible foods
As you start to be able to keep food down, choose foods such as rice, potatoes, toast, and bananas. This will allow you to recover some energy without disrupting your stomach. As you start to feel better, reintroduce food as part of your usual balanced diet. Avoid alcohol, caffeine, and foods high in sugar or fat.
Get plenty of rest
Whenever you're unwell, it's essential to give your body enough time to rest. Your body needs adequate rest in order to recover fully.
If the symptoms persist, or if in doubt, speak to a doctor or visit the accident & emergency department for immediate medical attention.
Article reviewed by Dr Vincent Lai, gastroenterologist at Gleneagles Hospital
(16 October 2018) Viral gastroenteritis (stomach flu). Retrieved 8 December 2021 from https://www.mayoclinic.org/diseases-conditions/viral-gastroenteritis/symptoms-causes/syc-20378847
(26 April 2020) Stomach Flu (Gastroenteritis). Retrieved 8 December 2021 from https://my.clevelandclinic.org/health/diseases/12418-gastroenteritis