Diarrhea

Diarrheal diseases occur often. They are often the result of a viral infection. Persistent diarrhea must be treated because it can lead to loss of fluid and sodium depletion.

At a glance

  • Diarrhea is often triggered by a viral infection, most often by the norovirus and rotavirus, which are very contagious.
  • The term diarrhea is used when the stool is very loose or is a liquid at least three times within a period of 24 hours.
  • Acute diarrhea typically lasts for a few days up to one week.
  • The body experiences a loss of liquid and sodium (electrolytes). It is important to restore the balance of fluid.
  • Persistent diarrhea must be treated.
  • Some gastrointestinal infections must be reported.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

Diarrhea: woman standing in front of toilet door holding her stomach.

What is a diarrheal disease?

Diarrheal diseases are very common. On average, adults experience diarrhea once a year, and children more often.

Diarrhea is typically caused by a viral infection. Often, the very contagious norovirus and rotovirus are the cause. However, bacteria such as salmonella or campylobacter can trigger a gastrointestinal infection (gastroenteritis).

In the case of normal diarrhea, it suffices to restore the balance of fluid and wait for the infection to pass. Severe or persistent diarrhea must be treated. It can lead to dangerous loss of fluid and sodium depletion. This can be dangerous in small children and the elderly.

What are the symptoms of diarrhea?

A gastrointestinal infection often begins suddenly with projectile vomiting or severe diarrhea. Diarrhea is characterized by a very soft or liquid stool, which occurs at least three times within a period of 24 hours.

Man sitting on a toilet, possibly with diarrhea.

Diarrhea is often accompanied by abdominal pain and cramps, as well as bloating. Symptoms can also include fever, and head and limb pain.

Important: Dizziness and circulation problems can occur if the body has lost too much liquid and sodium (electrolytes). In this case, a doctor should be contacted immediately. 

It is advisable to contact a doctor in the case of:

  • no improvement after 48 hours
  • high temperature/fever
  • blood in the stool
  • mucus in the stool
  • severe pain
Indications of diarrhea: no improvement after 48 hours, severe pain, high temperature (fever), mucus in the stool, blood in the stool.

What are the causes of diarrheal diseases?

There are a variety of causes of diarrhea. One of the most common causes is a gastrointestinal infection caused by the very contagious norovirus or rotovirus. It occurs most frequently in small children and the elderly. In Germany, bacterial gastrointestinal infections are typically caused by campylobacter or salmonella. Diarrhea can also occur when traveling. Depending on the country, unsanitary conditions can cause shigella, certain E. coli, or parasite infections.

Diarrhea is not only caused by infections, however. Other possible causes are:

  • unfamiliar food, for example during (long-distance) travel
  • food intolerances such as gluten or lactose intolerance
  • a “nervous intestinal tract” (irritable bowel syndrome)
  • chronically inflamed intestinal diseases such as Crohn's disease and ulcerative colitis
  • side effects from certain medications that can cause an imbalance in normal intestinal flora and sometimes trigger diarrhea; this is particularly the case with antibiotics.

How does diarrhea progress?

Acute diarrhea typically lasts for a few days up to one week. Diarrhea is considered persistent if it lasts longer than two weeks.

How can diarrhea be prevented?

In daily life hands often come in contact with viruses and bacteria. Pathogens can be transmitted via the stool, vomit, water, food, or contaminated objects. To protect oneself and others, it is important to regularly and thoroughly wash the hands. Hand sanitizer can also be useful during acute diarrhea. If a second toilet is available in the home, it is best if only the family member with diarrhea uses it until healthy again.

Clothing should be washed in hot water (at least 60 degrees Celsius). When preparing food, it is important to practice particularly good hygiene. A person suffering from acute diarrhea should not prepare meals for others.

Here are a few tips for preventing travel diarrhea. In subtropical or tropical countries, and depending on the hygienic conditions, it is best to avoid raw, non-peeled fruits and vegetables and to drink only bottled water. Fish and meat should be thoroughly cooked until well-done.

For infants younger than 6 months, the Standing Vaccination Committee (STIKO) recommends vaccination against the rotavirus. This oral vaccination should protect children from infection for approximately two to three years.

More information about diarrhea and how you can prevent it can be found at gesundheitsinformation.de.

How is diarrhea diagnosed?

The doctor will ask:

  • if the symptoms appeared suddenly or gradually.
  • how long the diarrhea has lasted and how often it occurs.
  • what the stool is like (appearance and consistency).
  • if there are other symptoms such as abdominal pain, vomiting, or fever.
  • what was eaten before the diarrhea began.

It is also important for diagnosis:

  • if any time was spent outside of the country.
  • if and if yes, which medication was taken or is being taken.
  • if allergies or intolerances are known.
  • if a chronic disease such as diabetes exists.

A stool or blood sample may be necessary in the case of bloody or persistent diarrhea or diarrhea with mucus. This helps determine which pathogen caused the infection.

How is diarrhea treated?

Diarrhea leads to a loss of fluids and electrolytes. It is important to restore the balance of fluid.

In the case of acute diarrhea, tea with sweetener and a salty cracker can help. Rice, bananas, or crisp bread (rusk) are gentle on the stomach and are often recommended in the case of acute diarrhea.

Coffee, fruit juices, lemonade, alcohol, and fatty dishes irritate the intestines. Therefore, it can be a good idea to avoid these foods and drinks.

What are the best foods to eat when you have diarrhea? Salty snacks, tea with sugar, rusks, bananas, rice.

Acute diarrhea in children and adults does not require special treatment. Treatment is necessary for young children and the elderly, and in cases of severe diarrhea. Such cases should be treated with a rehydration solution (also called electrolyte/glucose solutions) to restore the balance of fluids.

These are available in powder form at pharmacies or drug stores. The powder can be dissolved in water. These solutions contain salts, minerals, and dextrose.

If a rehydration solution is not available, for example while traveling, a substitute can be made. The following ingredients can be added to a liter of bottled or boiled water:

  • 4 teaspoons of sugar
  • ¾ teaspoon of table salt
  • a glass of bottled orange juice

To reduce the duration of the diarrhea, food or dietary supplements with probiotic microorganisms (probiotics) can help to supplement fluid intake and other treatments.

Depending on the duration and severity of the symptoms, other treatments can be used:

  • Medications such as racecadotril and loperamide calm the intestines. They can reduce the frequency of visits to the bathroom. Loperamide is not suitable for children under the age of twelve, and racecadotril requires a prescription for children.
  • Certain yeast tablets (Perenterol) are also sometimes recommended. They accelerate elimination of the pathogen and support restoration of the natural intestinal flora. Charcoal tables can also relieve symptoms. They are dissolved in water and then taken. However, there are no conclusive studies that can sufficiently substantiate the risks and benefits of these treatments. Yeast tablets are not suitable for the seriously ill or persons with compromised immune systems.
  • Antibiotics are effective against bacteria, but not viruses. Therefore, they are used to treat bacterial gastrointestinal infections only.

What else is important?

Some gastrointestinal infections must be reported. This means that a doctor or the local public health authority must be notified. For example, a substantiated norovirus or rotavirus, salmonella or campylobacter infection must be reported.

In general, a gastrointestinal infection in children under six years who attend a community institution such as a daycare or preschool must be reported. If an infection is diagnosed by a doctor, the doctor must report it to the responsible public health authority within 24 hours. The child may only return to daycare or preschool once he or she is diarrhea free for two days. This prevents other children from becoming ill.

There is a Protection Against Infection Act in Germany. It is intended to prevent infectious diseases and their spread. According to this act, persons who work in the food industry and have a suspected or confirmed case of a gastrointestinal infection or have salmonella may return to work only after three samples of stool have been tested for and are clear of pathogens. As a precaution, particular importance should be placed on hand hygiene in the workplace for the following four to six weeks.

In cooperation with the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen) (IQWiG). As at:

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