What Is Stomach Flu?


Ever had a significant discomfort in your stomach that seemed like it was sucking the life out of you because you ate something? You are feeling pains or cramps in your abdomen. This can sometimes lead to watery stool or bloody diarrhoea. There is also occasional muscle cramp or headache. If you have experienced these symptoms or currently do, you may be suffering from viral gastroenteritis. You may know this medical condition as stomach flu. This is different from influenza, which irritates your respiratory system. Instead, gastroenteritis attacks your digestive system.

This article will shed more light on stomach flu, its causes, signs, symptoms, and ways to treat it. It will also share insightful information on how they can manage it.

What is stomach flu?

Stomach flu is an infection that affects your intestines and causes watery diarrhoea, pain or cramping in your abdomen. Sometimes, it can lead to vomiting, nausea and fever. Despite being called a “flu”,  influenza does not cause this medical condition. Instead, the sickness is caused by a virus. Thus, the medical name viral gastroenteritis is better fitting.1 

Furthermore, the infection takes place in the intestines, not the stomach. Considering this fact, the flu vaccine cannot protect people against this illness, which makes you wonder why it was called “stomach flu” in the first place.

Causes of stomach flu

Stomach flu is caused by a viral stomach bug known as norovirus. This is a very contagious virus (transmissible by direct or indirect contact with an infected person) that causes vomiting and diarrhoea. It affects people of all ages.2

However, the major source of getting this virus is through consuming contaminated food or drinking contaminated water. You can also be infected with the virus by not washing your hands before eating. This is probably because you touched a contaminated surface before eating. 

Once inside your digestive system, norovirus multiplies itself to create enough copies to cause illness, then attack your intestines. Besides the viral stomach bug, another cause of viral gastroenteritis is food poisoning, caught from eating contaminated food. In simpler terms, food poisoning results from eating meals or snacks contaminated with salmonella or Escherichia coli. Like with norovirus, these microbes attack the intestines.3,4

Signs and symptoms of stomach flu

The symptoms of stomach flu are either due to the effects of these microbes on your gut, or  your immune system is fighting the viral infection.

Here are the signs and symptoms of viral gastroenteritis:5

  • Feeling sick or nauseous
  • Watery stool or diarrhoea containing blood or mucus
  • Stomach cramps or abdominal pain
  • Loss of appetite
  • Weakness or lack of energy
  • Feverish feeling or high body temperature
  • Headache or aching muscles in other parts of the body

These stomach flu symptoms stated above are common. However, an infected person suffering from viral gastroenteritis should visit a doctor if they experience more severe symptoms like:

  • Excessive vomiting and inability to retain bodily fluid
  • Severe dehydration that results in rapid heartbeat, saggy eyeballs, and inability to pass urine
  • The symptoms do not improve after a week or more.

Meanwhile, you should also visit a doctor if you meet the following requirements while suffering from viral gastroenteritis:

Management and treatment for stomach flu

Regardless of the cause, an infected person will have these symptoms within one or two days of contracting the virus. Meanwhile, viral gastroenteritis is an acute illness that people can recover from within 10 days.

Moreover, your body can fight against norovirus infection without the aid of treatment. All you need to do is manage yourself properly while your body fights against the viral infection. One thing to do is to drink water or healthy fluids to stay hydrated. 

Vomiting and watery stool are one of the stomach flu symptoms. When these occur, the infected person loses bodily fluid, leading to weakness and lack of strength..  Besides water, anyone with a norovirus infection can also take oral rehydration solutions. These supplements are more beneficial, especially to infants, elderly people, and those with  weak immune system or suffering from other health conditions.

Besides staying hydrated, avoid eating  “heavy food”. Instead, take healthy food, vegetables, and fruits. Eating spicy or oily food may result in further vomiting and stooling as the virus will keep working on any food that enters your guts. This will cause further loss of bodily fluid.

In addition, you can take the following over-the-counter (OTC) medications like loperamide (Imodium) and bismuth subsalicylate (Pepto-Bismol, Kaopectate).6,7 These medications can help treat and manage watery stool and diarrhoea. In turn, this will reduce the loss of bodily fluids.

You can also take pain relief medicines like paracetamol, ibuprofen, or other analgesics to alleviate the fever and pain, in addition to magnesium supplements to help with fatigue.8, 9


How is stomach flu diagnosed?

Your doctor will diagnose stomach flu based on the following symptoms: diarrhoea, nausea, vomiting, stomach pain, and fever. Experiencing more than one of these signs indicates that you are suffering from stomach flu.

In addition, stool test can detect norovirus and rule out a possible bacterial or parasitic infection.10

How can I prevent stomach flu?

You can prevent stomach flu by taking these measures:

  • Wash your hands after using the toilet, changing your toddler's diapers, and before eating
  • Cook your food properly in adequate heat of 160° Fahrenheit to kill bacteria or virus particles
  • Wash your food and vegetables thoroughly before eating
  • Clean and disinfect surfaces like kitchen tops, tables, and sinks regularly.

Who are at risks of stomach flu?

Everyone is at risk of contracting stomach flu. However, people over 60 years of age, pregnant women, toddlers, and patients with preexisting health conditions like HIV or cancer are more susceptible to the infection.

How common is stomach flu?

Stomach flu is a common health condition worldwide. However, it's difficult to estimate the percentage of infection each year because most people do not get clinically tested for it.

When should I see a doctor?

You should see your doctor if you experience the following:

  • Persistent stomach flu symptoms that last more than seven days
  • Severe dehydration and difficulty to pass out urine.
  • Bloody diarrhoea
  • Underlying health conditions like HIV, weak immune system, kidney diseases, or inflammatory bowel disease.


  • Stomach flu is a very common condition that affects many people. Norovirus is the leading cause of stomach flu 
  • The symptoms can vary from person to person; however, nausea, vomiting, diarrhoea, and abdominal pain are the most common 
  • These symptoms can be managed with rest, staying hydrated, and taking OTC like paracetamol
  • Always remember to wash your hands and cook your food properly to prevent the infection


  1. Bányai K, Estes MK, Martella V, Parashar UD. Viral gastroenteritis. The Lancet [Internet]. 2018 Jul [cited 2023 Aug 8];392(10142):175–86. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0140673618311280
  2. Robilotti E, Deresinski S, Pinsky BA. Norovirus. Clin Microbiol Rev [Internet]. 2015 Jan [cited 2023 Aug 8];28(1):134–64. Available from: https://journals.asm.org/doi/10.1128/CMR.00075-14
  3. Kunwar R, Singh H, Mangla V, Hiremath R. Outbreak investigation: Salmonella food poisoning. Medical Journal Armed Forces India [Internet]. 2013 Oct 1 [cited 2023 Aug 8];69(4):388–91. Available from: https://www.sciencedirect.com/science/article/pii/S0377123713000099
  4. Smith J, Fratamico P. Escherichia coli as other Enterobacteriaceae: food poisoning and health effects. In: Encyclopedia of Food and Health [Internet]. 2016 [cited 2023 Aug 8]. Available from: https://www.ars.usda.gov/research/publications/publication/?seqNo115=320379
  5. National Collaborating Centre for Women’s and Children’s Health (UK). Diarrhoea and vomiting caused by gastroenteritis: diagnosis, assessment and management in children younger than 5 years [Internet]. London: RCOG Press; 2009 [cited 2023 Aug 8]. (National Institute for Health and Clinical Excellence: Guidance). Available from: http://www.ncbi.nlm.nih.gov/books/NBK63844/
  6. Baker DE. Loperamide: a pharmacological review. Rev Gastroenterol Disord [Internet]. 2007 Jan 1 [cited 2023 Aug 8];7 Suppl 3:S11-8. Available from: https://europepmc.org/article/med/18192961
  7. Gorbach SL. Bismuth therapy in gastrointestinal diseases. Gastroenterology [Internet]. 1990 Sep 1 [cited 2023 Aug 8];99(3):863–75. Available from: https://www.sciencedirect.com/science/article/pii/0016508590909838
  8. Graham GG, Scott KF. Mechanism of action of paracetamol. American Journal of Therapeutics [Internet]. 2005 Feb [cited 2023 Aug 8];12(1):46. Available from: https://journals.lww.com/americantherapeutics/Abstract/2005/01000/Mechanism_of_Action_of_Paracetamol.8.aspx
  9. Bushra R, Aslam N. An overview of clinical pharmacology of ibuprofen. Oman Med J [Internet]. 2010 Jul [cited 2023 Aug 8];25(3):155–1661. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3191627/
  10. Hall AJ, Rosenthal M, Gregoricus N, Greene SA, Ferguson J, Henao OL, et al. Incidence of acute gastroenteritis and role of norovirus, georgia, usa, 2004–2005. Emerg Infect Dis [Internet]. 2011 Aug [cited 2023 Aug 8];17(8):1381–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3381564/
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Ochuko Atenaga

Second Class Upper Division, Psychology, University of Port Harcourt

My name is Ochuko, and I am a seasoned web content writer who simplifies the most complex ideas. For half a decade, I have written content on Blockchain, NFTs, Digital Marketing, eCommerce Development, G Health, Technology, Lifestyle, Tourism, Hospitality, and gambling. During this period, he has worked with top brands like Clario, CryptoGames3D, Amazix, AIKON, Progos Tech, Webzool, Zenith Chain, Jungle NFT Marketplace etc.

Leave a Reply

Your email address will not be published. Required fields are marked *

my.klarity.health presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818