Severe diarrhea causes the body to lose large amounts of water and salts. Because diarrhea often occurs at the same time as nausea and vomiting - both of which reduce dietary intake - it can lead to dehydration (excessive loss of water). Dehydration can weaken certain people and lead to more serious problems.

What causes Diarrhea?

Infectious diarrhea, sometimes called "intestinal flu," may be caused by a virus, bacteria, and parasites such as amoebae and giardia. People sometimes come into contact with these sources of infection through contaminated food or water, public swimming pools, and communal hot tubs. Visitors to foreign countries are susceptible to traveler’s diarrhea, also caused by food or water contaminated by bacteria.

At least 100 diseases can also cause diarrhea. Some of these are ulcerative colitis (a condition that causes sores to form in the inner lining of the colon and rectum), Crohn’s disease (a condition in which the wall of the intestine becomes sore, inflamed, and swollen), some forms of intestinal cancer, and some disorders of the intestine that lead to poor digestion of food. Nervous diarrhea, one form of the disorder, occurs with irritable bowel syndrome, which is caused by factors such as an oversensitive colon muscle, poor absorption of certain carbohydrates (sugars), nervous stress, and hormones.

Many medications, including antibiotics, antacids that contain magnesium and drugs that change the movements or fluid of the colon, can also cause diarrhea. In addition, frequent use of laxatives may cause damage to the nerves and muscles of the colon, which leads to diarrhea.

Tips for Travelers

When you travel in developing countries, avoid water and ice that are not commercially processed; unwashed and uncooked foods such as fruits, salads, and raw seafood; and food bought from unlicensed sellers. If you develop mild diarrhea, drink lots of bottled water, soft drinks (and sports drinks), and clear soups to prevent dehydration.  More information on travelers' diarrhea is available online.

Diagnosis

Diagnosis of a particular infection is often not necessary for mild diarrhea, which usually lasts only a day or two. However, infections with salmonella (such as typhoid fever), shigella (dysentery), amoebae, and some other organisms are more serious and may require laboratory examination of the stools, urine, or blood to determine the source of the problem.

Treatment

A mild case of diarrhea can usually be cured with bed rest and plenty of fluids by mouth (sports drinks, such as Gatorade, are good). An over-the-counter medication may also help. More severe cases may require a stay in the hospital and intravenous fluids to replace lost water and salts.

If you have mild diarrhea for longer than three days, or if your diarrhea becomes severe and you develop a fever, make an appointment to see your physician.

Source: St. Luke's Texas Liver Institute
Last Updated: May 13, 2004