International Classification (ICD) A00.-
Symptoms Abdominal pain, unformed stool, Fever, Nausea
Possible causes Antibiotics, Lactose intolerance, Intestinal infection, increased bowel activity, above average fluid in the intestine, Viruses, bacteria and fungi
Possible risk factors Food intake in foreign regions, Hygiene deficiency, Irritable bowel syndrome



Diarrhoea (diarrhoea) is a symptom that is spoken of as soon as:

  • there is an urge to defecate more frequently than 3 times a day
  • the stool has a changed, liquid consistency
  • the quantity is above average (> 250 g/d)

If the diarrhoea lasts up to 2 weeks, doctors speak of acute diarrhoea, anything beyond this is called chronic diarrhoea.

Short-term diarrhea (a few days) is not harmful for healthy adults. Every third person is affected by diarrhoea once a year


Diarrhea can be caused by diseases that affect the function of the small and large intestines. There are 2 main causes:

  • increased intestinal activity (accelerates intestinal transit)
  • above-average amount of fluid in the intestine

Acute diarrhoea

  • Food poisoning: bacteria (staphylococci, salmonella) attack the digestive tract and produce toxins that act within a few hours.
  • Intestinal flu: Viral or bacterial infection.
  • Traveler's Diarrhea: Travelers often suffer from infections of bacteria (E. Coli), less commonly viruses or parasites.
  • Medications: Antibiotics and other drugs attack or destroy the intestinal flora. Normally, the symptoms subside after the medication is stopped. Due to the necessity of these drugs in certain diseases, this side effect is tolerated.
  • Food intolerance: Lactose intolerance and other intolerances lead to diarrhoea because e.g. dairy products cannot be completely digested.

Chronic diarrhoea

  • Irritable bowel syndrome (intestinal irritation without complications)
  • Chronic intestinal inflammation (ulcerative colitis, Crohn's disease)
  • Chronic intestinal infection (parasites e.g. amoebae, Clostridium difficile, lamblia)
  • Drug abuse (laxatives)

Far less frequently, metabolic disorders, tumours or operations are responsible:

  • Hyperthyroidism (overactive thyroid gland)
  • Pancreatic carcinoma (cancer of the pancreas)
  • Intestinal surgery


In diarrhoea, the stool can be watery, mushy, greasy (greyish, strong-smelling, oily) or even bloody. In addition, there may be flatulence, abdominal colic, loss of appetite and nausea to vomiting.

A doctor should be consulted as soon as they show any of the following symptoms:

  • Fluid cannot be supplied or is not supplied adequately.
  • Dehydration sets in (little and dark urine, lack of strength, drying of the mucous membranes).
  • fever
  • bloody or fatty stools
  • Symptoms develop after a stay abroad
  • long lasting diarrhoea
  • no improvement, although antibiotics suspected as the cause were discontinued


Acute diarrhoea

In acute diarrhea, even a history (medical history) may be sufficient to make the diagnosis. In case of prolonged symptoms and/or fever, the following examinations may be informative:

  • Stool examination (germs, blood)
  • Blood test (signs of inflammation, germs)
  • Exclusion of infectious diseases (after a stay abroad) e.g. typhoid fever, cholera, amoebic dormancy, lambiliasis, schistosomiasis

Chronic diarrhoea

Several examinations are necessary to diagnose chronic diarrhea:

  • Colonoscopy (colonoscopy) with biopsy (tissue sampling), alternatively, enema with contrast medium and imaging procedures.
  • Sonography of the abdomen (abdominal ultrasound)
  • Gastroscopy (gastroscopy of the stomach), gastroduodenoscopy (gastroscopy of the small intestine) and biopsies
  • CT (computer tomography) of the abdomen


Acute diarrhoea

  • Since bacteria or viruses are usually responsible and complications are not to be expected, the following strategies are mainly pursued:
  • Ensuring fluid and electrolyte intake (salts), possibly home remedies (grated carrots, apples, mashed bananas).
  • Electrolyte powders and infusions for vulnerable groups such as pregnant women, children, the elderly.
  • Medicines against diarrhoea should only be used in exceptional cases (bus journey, dangerous loss of water) as the pathogen then remains longer in the intestine and damages it.
  • antispasmodic medicines alleviate abdominal colic
  • Antibiotics are useful if the immune system is unable to cope with triggering bacteria on its own. Suitable preparations are prescribed by the doctor after a stool examination.
  • In the case of food intolerances, appropriate foods should be avoided.

Chronic diarrhoea

Symptomatic treatment is not sufficient here, the cause must be cured.


  • Mild to moderate diarrhoea can be counteracted with plenty of fluids (3-4 l/d). Sugar, salt and potassium are necessary in appropriate quantities, otherwise the fluid cannot be stored.
  • Cola and similar soft drinks are not suitable for treatment. They contain too much sugar, too little sodium and usually no potassium.
  • Children under 5 years of age should not be supplied with home remedies, but with special electrolyte solutions (pharmacy).

For adults the following can help:

  • homemade electrolyte solution: ½ tsp salt + 5 tsp dextrose + 0.5l boiled water. Flavour with orange juice.
  • Ensure salt intake through clear, salted soups.
  • bananas and apricots are suitable sources of potassium
  • consume dairy products only to a limited extent during the first few days.
  • Eat normally as soon as appetite sets in.

Caution: In case of severe diarrhoea, always consult a doctor!


Acute diarrhea usually does not last more than a week. However, the exact duration depends on the immune system, cause and any complications.

The prognosis for chronic diarrhoea depends on the underlying disease. Prolonged diarrhea and subsequent fluid loss can lead to circulatory and renal failure. Risk groups are infants, young children, pregnant women, the elderly and the immunocompromised, as well as malnourished people.



Since many cases of diarrhea are the result of infections with bacteria or viruses, hygiene is crucial to prevent.

  • Foods that are susceptible to salmonella should be stored separately and below 10°C. These include poultry, game, fish and seafood. These should also always be prepared separately.
  • Poultry, fish and meat must be cooked thoroughly. Minced meat should be consumed on the day of production.
  • Dishes (including pastries) containing raw egg must be eaten immediately.


When travelling to regions where hygiene standards are low, always ensure that your food is peeled, boiled or grilled. In addition, the following precautions may be helpful:

  • Timely travel vaccinations (e.g. typhoid).
  • Washing your hands thoroughly before eating
  • Peel fruit and vegetables
  • Disinfecting drinking water (e.g. boiling)

Editorial principles

All information used for the content comes from verified sources (recognised institutions, experts, studies by renowned universities). We attach great importance to the qualification of the authors and the scientific background of the information. Thus, we ensure that our research is based on scientific findings.
Danilo Glisic

Danilo Glisic

As a biology and mathematics student, he is passionate about writing magazine articles on current medical topics. Due to his affinity for facts, figures and data, his focus is on describing relevant clinical trial results.

Dr. med. univ. Bernhard Peuker, MSc

Dr. med. univ. Bernhard Peuker, MSc

Bernhard Peuker is a lecturer and medical advisor at Medikamio and works as a physician in Vienna. In his work, he incorporates his clinical knowledge, practical experience and scientific passion.

The content of this page is an automated and high-quality translation from DeepL. You can find the original content in German here.



Your personal medicine assistent

afgis-Qualitätslogo mit Ablauf Jahr/Monat: Mit einem Klick auf das Logo öffnet sich ein neues Bildschirmfenster mit Informationen über medikamio GmbH & Co KG und sein/ihr Internet-Angebot: medikamio.com/ This website is certified by Health On the Net Foundation. Click to verify.

Search our database for drugs, sorted from A-Z with their effects and ingredients.


All substances with their common uses, chemical components and medical products which contain them.


Causes, symptoms and treatment for the most common diseases and injuries.

The contents shown do not replace the original package insert of the medicinal product, especially with regard to dosage and effect of the individual products. We cannot assume any liability for the correctness of the data, as the data was partly converted automatically. A doctor should always be consulted for diagnoses and other health questions. Further information on this topic can be found here.