Dossier: Home remedies

Hit by the stomach flu! What can you do?

With symptoms including nausea, vomiting and diarrhoea, the stomach flu can be really nasty. Fortunately, there are ways to ease the symptoms and fend it off.

Text: Nicole Krättli; photo: iStock

Despite the name, stomach flu has nothing to do with the “true” flu, influenza. In fact, gastroenteritis, which is the medical term for this illness, is an inflammation of the mucous membranes in the stomach and small intestine. This inflammation causes, among other things, very unpleasant vomiting and diarrhoea. Stomach flu is most often caused by viruses, primarily noroviruses and rotaviruses. But bacteria such as Campylobacter, Salmonella and certain strains of Escherichia coli can also trigger a gastrointestinal infection. As these infections are very contagious, almost everyone will suffer from gastroenteritis at least once in their life.

Stomach flu: causes

Infectious gastrointestinal illnesses are transmitted through a variety of routes depending on the pathogen. In Switzerland, viral gastroenteritis is particularly widespread, explains Andreas-Paul Müller, specialist in gastroenterology at GastroZentrum Hirslanden in Zurich. However, bacterial gastrointestinal infections can also occur, often due to poorer hygiene conditions on trips abroad.

  • Infection via food: Raw meat, eggs, fish, salad, vegetables and fruit are the most common carriers of bacteria such as Salmonella. However, hidden pathogens that cause diarrhoea can also be found in water and other drinks. 
  • Infection via objects: Surfaces such as toilets, door handles, handrails and fittings can also be contaminated with germs. If you touch them and then touch your mouth, the germs can enter the digestive tract.
  • Human-to-human transmission: Direct transmission from person to person can occur through droplet infection. Pathogens spread via droplets of saliva that are released into the air when sneezing, coughing or speaking and are absorbed via the mucous membranes of another person.
  • Animal-to-human transmission: Contact with farm animals can also be a source of infection. Chickens, goats and sheep, for example, can transmit pathogens such as Salmonella, Campylobacter or EHEC bacteria to humans via direct contact.

Stomach flu symptoms

Gastroenterologist Andreas-Paul Müller explains that the symptoms of stomach flu are often not immediately noticeable. It can take up to two days for the first symptoms to appear. In contrast, the symptoms of food poisoning often appear just two to four hours after eating the food in question.

The first and most common symptoms are nausea and vomiting. Diarrhoea, stomach cramps and abdominal pain often follow. The duration of symptoms varies. In the vast majority of cases, they disappear after two or three days without medical treatment. “It is important to bear in mind that diarrhoea, nausea and vomiting can have other causes. So it’s always worth talking to a doctor if the symptoms last longer than two or three days,” says Dr Müller.

Stomach flu: pregnant women, babies and elderly most at risk

Gastrointestinal infections can be particularly severe in older people and/or people with a weak immune system as well as pregnant women, babies and young children. “The loss of fluids caused by persistent diarrhoea poses the risk of dehydration. In this case, those affected should definitely seek medical advice,” says Dr Müller. But even people who don’t have any obvious risk factors should consult a doctor immediately if the symptoms become unbearable or if the following symptoms occur:

  • Blood in stool
  • Very high temperature
  • Circulatory problems, severe drowsiness, confusion or muscle cramps
  • Immediate vomiting after fluid intake

How to avoid the stomach flu

To avoid catching the stomach flu, it is most important to wash your hands regularly. You should also observe the following rule, particularly when abroad: “Cook it, peel it or forget it!” adds Müller. “When travelling in countries with poorer hygiene conditions than Switzerland, it’s a good idea to only eat things that have been cooked beforehand or that you can peel yourself.”

During the acute phase of the illness, it is advisable for healthy and sick people to use the bathroom and kitchen separately if possible. And these rooms should be cleaned regularly and well ventilated. Please also bear in mind that the sick person’s bed linen, towels and flannels should be washed at a temperature of at least 60 degrees Celsius. And dishes should be cleaned in the dishwasher at the highest possible temperature.  

Treatment: drink plenty of fluids

Although a viral stomach infection usually resolves on its own, it is still important to drink plenty of liquids while the illness runs its course. “During the acute phase, those affected should drink at least 2 litres a day during the acute phase to cover their fluid requirements. It’s best to drink still water, herbal tea and broth to replenish lost electrolytes,” says Dr Müller. Drinking cola as a cure for a bad stomach is a myth, he explains. “Sugar is not at all conducive to a stomach flu.” In addition to avoiding sugary drinks such as fruit juice, fizzy drinks and energy drinks, you should also stay away from coffee and alcohol.

High-risk groups such as young children, pregnant women and the elderly should drink electrolyte solutions. These contain a balanced mixture of dextrose, salts and minerals and are available in pharmacies. In case of severe diarrhoea, activated charcoal can also help to bind the irritating toxins to help the intestines recover.

Should you take antibiotics when you have the stomach flu? Best not

You should never take antibiotics without a medical prescription. “Antibiotics only work on illnesses caused by bacteria. But the stomach flu is often triggered by a virus. Depending on the course of the illness, taking antibiotics not only doesn’t help, it can even be really dangerous,” warns Müller. This is the case if Escherichia coli bacteria are involved. “Combined with antibiotics, coli bacteria can release toxins that can lead to death in the worst case. It is therefore essential that you see a doctor to clarify what is causing the symptoms,” he adds.

Eat foods that are easy on the stomach during and after the stomach flu

It is better to give your body plenty of rest and avoid physical exertion to allow your immune system to focus on fighting the pathogen. In the first acute phase, it is a good idea to eat foods that are gentle on the stomach. Avoid fats, fibre and foods that are hard to digest or irritating and see what does your body good. Rusks or stale bread, porridge, mashed potatoes without butter and milk, soup or broth made from carrots or courgettes, and bananas are ideal. Step by step, you can expand your diet to include foods such as rice or pasta.

About the expert

Dr Andreas-Paul Müller is a specialist in gastroenterology at GastroZentrum Hirslanden in Zurich. His core areas of expertise include the diagnosis of gastric, intestinal, pancreatic and liver diseases, interventional endoscopy and diagnostic and therapeutic proctology.

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