Definition and Overview

Diarrhea is a medical condition wherein the patient has at least three loose or liquid bowel movements a day. It is one of the most common types of diseases experienced by any age group and is especially common in children. The most significant complication of diarrhea is dehydration, which is a condition resulting from a massive loss of body water and electrolytes. When diarrhea ensues, body fluid and electrolytes are eliminated from the body before they are adequately absorbed. Dehydration is the state wherein the person's ability to take in fluids is not quick enough to replace the losses from the diarrhea. Most mortalities from diarrhea occur in the extremes of ages: either the very young or the very old.

The main categories of diarrhea are the following:

  • Chronic diarrhea - is the type that occurs for more than two weeks.

  • Gastroenteritis – also called as stomach flu that is typically associated with vomiting.

  • Acute gastroenteritis - this is the type of diarrhea where there is inflammation of the bowels.

  • Dysentery - characterized by blood in the pus or mucus in the stool.


There is a myriad of causes of diarrhea. The most common is the infection of the bowels caused by a bacteria, a virus or a parasite. These infections are usually acquired from contaminated water or food. Diarrhea may also result from eating food that upsets the digestive system and from allergies to specific food or ingredients. Certain medications are also known to cause diarrhea, such as antibiotics, chemotherapy drugs and laxatives that contain magnesium.

Diarrhea may also be a symptom of another medical condition, such as malabsorption syndromes, inflammatory bowel diseases, namely ulcerative colitis and Crohn's disease, and irritable bowel syndrome or IBS. Another common cause is lactose intolerance, wherein the person experiences loose stools after drinking milk or consuming other dairy products. Less common causes include disorders of the nerves that supply the intestines, removal of a portion of the stomach or the small intestines, and radiation therapy.

Key Symptoms

Diarrhea has various signs and symptoms. The most common and notable is having watery, liquid stools. It is important to note that the passage of red stools is suggestive of intestinal bleeding and may be a sign of more serious disease or infection. Thick, tarry black stools are also a sign of bleeding in the stomach or the upper bowels.

Patients with diarrhea usually experience abdominal cramps, as well. On some occasions, diarrhea is accompanied by some abdominal discomfort or pain. Severe abdominal pain is not typical and, if present, may be a sign of more severe illness. If diarrhea results in dehydration, the condition becomes an emergency and may potentially be lethal. Patients who experience dehydration are usually thirsty and have dry throats. In older patients, the skin appears to be loose, and they may become very sleepy, confused or develop changes in behavior. Infants and children who are dehydrated are noted to have sunken eyes and dry mouths. Urination is also less frequent than usual.

Who to See and Types of Treatments Available

Diarrhea can generally be treated at home. Treatment usually includes the removal of offending food components in the diet combined with proper hydration or replacement of lost fluids and electrolytes. Oral rehydration solutions are widely available and can be used to replace these losses.

In some cases, however, diarrhea may become severe and life-threatening. If you’re experiencing diarrhea, it’s crucial that you go to a hospital emergency department or consult a health care professional particularly if you experience signs and symptoms of dehydration. This is crucial particularly if you are unable to eat or drink anything and develop other signs of a potentially serious condition, such as vomiting, severe abdominal pain, blood in the stools or high-grade fever.

Also, elderly patients and those with concomitant medical diseases, including diabetes, kidney failure, and heart disease, should also seek consult if they develop diarrhea. Patients who are immunocompromised, such as those with HIV, should likewise contact a health care provider because they are at a higher risk of experiencing complications of diarrhea. Finally, if the diarrhea does not improve over the first two or three days, or if the symptoms appear to worsen, the patient should see a doctor immediately. In these cases, the patient may need to be admitted to the hospital where an intravenous line delivering fluids and electrolytes to the body may be inserted.


  • National Health Services - Diarrhea treatment.
  • Kids Health Organisation – Causes of Diarrhea.
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