Viral Gastroenteritis - Causes, Symptoms & Treatment

Viral gastroenteritis, often referred to as the stomach flu, is a common condition that is usually caused by a stomach bug or sickness bug. It can be unpleasant as gastroenteritis symptoms include sickness and diarrhoea.

Just how long does gastroenteritis last? Or is gastroenteritis contagious? Typically, it will clear up by itself within a week, however, it can be easily caught by others around you. It is important that you stay at home and not go to work. If your child has viral gastroenteritis they should not go to school.

Knowing what to eat after vomiting or what to eat when you have diarrhoea can be difficult as you won’t want to make your stomach flu symptoms worse. Although it is not dangerous, if you become dehydrated this can lead to further problems.


The main symptoms of viral gastroenteritis include:

  • Feeling sick or being sick
  • Diarrhoea
  • A mild fever
  • Loss of appetite
  • Aching limbs
  • Headaches

Stages of viral gastroenteritis

Incubation period

The incubation period is the amount of time between becoming infected and developing symptoms. With viral gastroenteritis this is usually between 24-48 hours but it can vary.

Symptoms appear

You will start to notice symptoms such as abdominal pain, vomiting or diarrhoea. Once you have been in close contact with an infected person it will take time for your symptoms to appear.

Symptoms worsen and peak

After a short period of time you will begin to notice that your symptoms have gotten worse. As your symptoms worsen it is important to drink lots of fluid to prevent dehydration.


It can take up to a week to recover from viral gastroenteritis. You should make sure you are getting plenty of rest when you are recovering.

You should remain at home and if you have babies and young children with it you should avoid sending them to nursery or school.


Viral gastroenteritis is usually caused by a bacterial or viral tummy bug.

Many different viruses can be a cause including rotavirus, sapovirus and astrovirus, however, norovirus[1] is the most common cause.


Your doctor can diagnose viral gastroenteritis based on your symptoms. In some cases they might want to take a stool sample to establish what organism is making you unwell.

When to see your GP

When infants and young children have gastroenteritis it is important that they see a GP straight away.

In adults, you should see a doctor if you notice blood in your stool, you can’t keep down any fluids with signs of dehydration, you have a high temperature or if your symptoms don’t get better.


There is no specific treatment for viral gastroenteritis, however there are medical treatments and things you can do at home to help.

Medical treatments

In some cases of viral gastroenteritis adults can purchase over the counter (OTC) medications.

Iopromide (Imodium) has the ability to help stop diarrhoea. Bismuth subsalicylate (Pepto-Bismol, Pepti-Calm and Bisbacter) can also help with diarrhoea. These should not be used to treat children.

Alternative treatments

Fresh air

Ventilate your room with fresh air where it is possible. If you choose to go outdoors for fresh air make sure that you are keeping your distance from other people to prevent the risk of spreading the illness.

Take regular sips of a cold drink

To remain hydrated, it is important that you continue to drink. Take small sips of water or sips of sports drinks to prevent yourself from becoming dehydrated. You can also opt for oral rehydration solutions. Even if you are struggling to keep fluids down it is important to continue drinking.

Distract yourself

To stop yourself thinking about feeling sick or unwell you should try and distract yourself with something you enjoy. Don’t overdo it, maybe watch your favourite film or read a book to take your mind off things.

Foods and drinks containing ginger

You should try and eat foods containing ginger. A ginger green tea is an option to help settle your stomach. It is a natural treatment for diarrhoea. You want to make sure that the food and drinks containing ginger are also bland foods as you don’t want to make your diarrhoea worse.

Avoid laying flat on your back

You should try to avoid laying on your back, even when you are sleeping. Laying on your back can make your symptoms worse. It can also increase the feeling of nausea.

What to eat/drink after vomiting/diarrhoea

The BRAT diet

The BRAT diet stands for bananas, rice, applesauce and toast. These foods are gentle on your stomach and are what you should be eating after sickness and diarrhoea.

What foods to avoid when you have viral gastroenteritis

You should try to stay away from foods that are high in fat, caffeine, high sugar, spicy, and dairy products. All of these will make you feel worse and can even worsen your symptoms.

You should also avoid fizzy drinks. When trying to keep hydrated you should stick to water and fruit juices.


To prevent viral gastroenteritis you should practise washing your hands regularly with soap and water.

Where possible you should try to avoid coming into contact with anyone who has had it recently.

Olivia Malone - Medical Content Writer
James O'Loan - CEO & Superintendent Pharmacist
James O'Loan , CEO & Superintendent Pharmacist on 18 June 2024
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