Foto von Mutter und Tochter (PantherMedia / monkeybusiness)

Diarrhea is very common: In Germany, for instance, adults get it once a year on average, and it is even more common in children. It is usually caused by viruses, the most common of which are the highly contagious norovirus and rotavirus. Infectious diarrhea can also come from bacteria such as Salmonella or Campylobacter.

In normal cases of diarrhea, you can usually just replace the fluids you lose and wait until the infection goes away. But more severe or longer lasting diarrhea needs to be treated because it can lead to the loss of dangerously high levels of fluid and salt, especially in young children and older people.


The infection often starts suddenly with projectile vomiting or severe diarrhea. It is considered to be diarrhea if you have more than three very loose or liquid bowel movements within 24 hours. Diarrhea is often accompanied by stomach ache, cramps and bloating. As well as nausea, diarrhea can also be associated with fever, headache and achy joints.

Dizziness and problems with circulation could be signs that your body has lost too much liquid and salts (electrolytes). If that happens, immediate medical attention is needed. Other reasons to seek medical help for diarrhea include:

  • No improvement after 48 hours
  • High fever
  • Blood in stool (reddish or blackish stool)
  • Mucous coating on the stool
  • Severe pain

Causes and risk factors

Diarrhea can have a number of different causes. The most common is an infection arising from the very contagious noroviruses and rotaviruses, which most often affect children and older people Bacterial diarrhea is usually caused by Campylobacter or Salmonella bacteria. When you travel to places that lack sanitary conditions, Shigella, E. coli bacteria and parasite infections can also cause diarrhea.

Diarrhea can also have other causes besides infections, including the following:

  • Food you are not used to (for example while traveling abroad)
  • Food intolerances like gluten or lactose intolerance
  • Irritable bowel syndrome (IBS, also called “spastic colon”)
  • Chronic inflammatory bowel diseases like Crohn’s disease or ulcerative colitis
  • Side effects of medication: antibiotics in particular sometimes cause diarrhea because they also attack normal gut flora.

Learn more


Acute diarrhea is usually over within a few days or a week. Diarrhea that lasts for more than two weeks is considered to be chronic.


Acute diarrhea usually doesn't have any lasting health effects. But it is important to seek medical advice if you have severe, watery diarrhea or frequent vomiting with major loss of fluids, in order to prevent circulatory collapse. This is especially true for babies and toddlers, people with weakened immune systems, and older people. Because older people often feel less thirsty in general, and may not drink enough as a result, they are at greater risk of dehydration.

The following could be signs of dehydration:

  • Worsening general state of health
  • Sunken eyes, cheeks or face
  • Faster breathing or higher pulse than normal
  • Skin that lacks elasticity: When you pinch some of the skin on your arm or belly and let go, it doesn't bounce back to its original position, and a visible skin fold remains.
  • Early signs of dehydration also include feeling very thirsty, dazed, having dark urine, no urge to urinate, dry eyes, dry lips or a dry tongue.
  • Older people may sometimes have chest pain or muscle cramps.


When you see the doctor you will first be asked:

  • whether your symptoms started suddenly or gradually,
  • about the consistency and appearance of your bowel movements,
  • how long and how frequently you have had diarrhea,
  • whether you also have symptoms such as stomach ache, vomiting or fever, and
  • what you had to eat before getting diarrhea.

It is also important for them to know

  • whether you have been traveling recently,
  • what medications you have taken,
  • whether you have any diagnosed allergies or intolerances, and
  • whether you have a chronic disease, such as diabetes.

If you have bloody or chronic diarrhea, a sample of your stool or blood may be needed to find out what kind of infection you have. The same applies if there is mucus in the diarrhea.


Viruses and bacteria can spread through contact with stool, vomit and contaminated objects, water or food.

This means that frequently washing your hands thoroughly is essential if you have acute diarrhea, in order to protect others from infection. A hand disinfectant can also help. If you have a second bathroom at home, whoever is ill can be the only one to use it.

Clothes should be washed at temperatures above 60 degrees Celsius (about 140 degrees Fahrenheit) if possible. It is important to pay attention to hygiene in the kitchen and while preparing food. Anyone with acute diarrhea should not prepare food for others.

Children with diarrhea can only return to day care or school after they have had two days with no diarrhea.

When traveling to tropical or subtropical climates you may need to avoid uncooked, unpeeled fruit and vegetables and not drink tap water. Don't eat undercooked meat or fish.


You lose fluids and electrolytes when you have diarrhea, so it is important to replace them. For acute, non-severe diarrhea you usually just need something like tea with sugar and some salted crackers. Foods that are gentle on the stomach is recommended too, such as rice, bananas or rusk bread. Some people also avoid coffee, fruit juices, sodas, alcohol and fatty foods to keep from irritating their bowel even more.

Acute, non-severe diarrhea does not require special treatment in adults and teenagers. But it is a good idea for young children and older people, as well as people with more severe diarrhea, to replace fluids and electrolytes by using oral rehydration salts (electrolyte/glucose solutions) from the pharmacy. These are powders containing salts, minerals and glucose that can be dissolved in water. If these solutions are not available (for instance, while traveling) the following ingredients can be stirred into one liter of bottled or boiled water:

  • Five tablespoons of sugar
  • One and a half level tablespoons of salt
  • One glass of packaged orange juice

In addition to drinking fluids and using other treatments, foods or dietary supplements that have probiotic microorganisms (probiotics) in them can help to make the diarrhea go away faster.

Depending on how severe the symptoms are and how long they last, other treatments may be considered too:

  • Drugs like loperamide or racecadotril can help to slow down the activity of the bowel and lower the number of times you need to go to the bathroom. Loperamide is not suitable for children under the age of twelve years, and racecadotril is prescription-only for children.
  • Sometimes certain types of yeast tablets (Perenterol) are also recommended. These tablets are thought to help the body get rid of the germs faster and to support natural gut flora. Charcoal tablets dissolved in water can also be taken to relieve diarrhea symptoms. But there is a lack of good-quality research in this area so no conclusions can be drawn about the benefits and harms of these treatment options.
  • Antibiotics are only an option if the infection is bacterial. They can't fight viruses.

Research summaries

Further information

It is mandatory to report certain gastrointestinal diseases. This means that your doctor is required by law to inform the local health authorities. This is the case for diagnoses of norovirus, rotavirus, Salmonella or Campylobacter infections.

For children under the age of six years who spend time with other children (day care, preschool), it is generally mandatory to report infectious diarrhea. A child who is ill can only go back two days after the symptoms have gone away. A note from the doctor is not needed.

In Germany, the Infection Protection Act (Infektionsschutzgesetz) prevents people in the food industry who are thought to have infectious diarrhea from going to work. They are also advised not to return to work until they have been symptom-free for at least two days. Depending on the cause, a doctor might have to verify that their stool is no longer contaminated. For the next four to six weeks, the occupational regulations for hand hygiene should be followed particularly carefully.