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Acute (sudden) diarrhoea is usually due to an intestinal infection that may be caused by bacterial toxins – a condition known as food poisoning – or by a virus. Diarrhoea is usually caused by microbes that enter the body via the hands, food or water. An epidemic spreading via food or water must be identified rapidly and immediate measures must be taken. Pathogens that commonly cause diarrhoea include norovirus and sapovirus, both of which are members of the calicivirus family. Norovirus spreads extremely easily and is present in faeces for 2 to 8 weeks. 

Persistent diarrhoea may be caused by a variety of factors, and its cause should always be established. Diarrhoea is considered persistent if the person has bowel movements more than 3 times daily and diarrhoea has lasted more than 4 weeks.

Diarrhoea is one of the most common infectious diseases among travellers. Depending on the country of destination and the country of origin, 20–60% of people develop traveller’s diarrhoea. Traveller’s diarrhoea may be caused by bacteria, viruses or parasites. It usually lasts 3 to 5 days.


In addition to frequently passing loose stools, the symptoms may involve blood or mucus (slime) in diarrhoea, feeling sick, vomiting, cramp-like abdominal pain and loud, increased bowel sounds. The symptoms may also include fever and aching limbs.


Make sure you observe good hand hygiene to prevent the spread of infection. After passing stools, you should always wash your hands with soap and water and dry them with a single-use towel or paper. In the case of diarrhoea associated with norovirus or Clostridium difficile, it is important also to use hand sanitisers (hand rubs). 

Diarrhoea caused by viruses will resolve spontaneously; the most important thing is to keep well hydrated. Drinks suitable for a person with diarrhoea include diluted juices, tea, water, berry soups and kissels, as well as meat and vegetable broths. Drinks and foods that can make diarrhoea worse include milk, caffeinated drinks, fresh bread and pastries, fatty fried foods, peas, beans, onion, swedes, cabbages, mushrooms, asparagus and drinks and foods that contain sweeteners.

When should I seek treatment? 

You should seek treatment if your symptoms last for over a week despite self-care (watery diarrhoea more than 3 times daily, vomiting or abdominal pain) or if you have any of the symptoms listed below. After a stomach flu it’s normal to have loose stools and a sensitive stomach for a few weeks.

SymptomYou should seek treatment for the following reason:
blood in vomit sign of a serious stomach
starts during or after treatment with antibiotics (bloody or watery diarrhoea more than 3 times daily)may require medication or a
change of medication
intense vomiting and fever during
or soon after a trip abroad
may require additional
examinations ortesting
vomiting in a person who works with foodrequires isolation from work
until the cause is established
or the symptom disappears
other abnormally heavy or persistent vomiting or impaired
overall condition; persons with a serious underlying disorder (such as diabetes) or specific circumstances (such as pregnancy)
fever and bloody diarrhoea
worsening local abdominal pain and vomiting (appendicitis)

FSHS General Practitioner / 23 February 2023

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