What is Diarrhea?
Diarrhea—loose, watery stools occurring more than three times in one day—is a common problem that usually lasts a day or two and goes away on its own without any special treatment. However, prolonged diarrhea can be a sign of other problems. People with diarrhea may pass more than a quart of stool a day.

Diarrhea can cause dehydration, which means the body lacks enough fluid to function properly. Dehydration is particularly dangerous in children and the elderly, and it must be treated promptly to avoid serious health problems. People of all ages can get diarrhea. The average adult has a bout of diarrhea about four times a year.

What causes Diarrhea?
A few of the more common causes of diarrhea are:

Bacterial infections. Several types of bacteria, consumed through contaminated food or water, can cause diarrhea. Common culprits include Campylobacter, Salmonella, Shigella, and Escherichia coli.

Viral infections. Many viruses cause diarrhea, including rotavirus, Norwalk virus, cytomegalovirus, herpes simplex virus, and viral hepatitis.

Food intolerances. Some people are unable to digest some component of food, such as lactose, the sugar found in milk.

Parasites. Parasites can enter the body through food or water and settle in the digestive system. Parasites that cause diarrhea include Giardia lamblia, Entamoeba histolytica, and Cryptosporidium.

Reaction to medicines, such as antibiotics, blood pressure medications, and antacids containing magnesium.

Intestinal diseases, like inflammatory bowel disease or celiac disease.

Functional bowel disorders, such as irritable bowel syndrome, in which the intestines do not work normally.

What are the symptoms?
Diarrhea may be accompanied by cramping abdominal pain, bloating, nausea, or an urgent need to use the bathroom. Depending on the cause, a person may have a fever or bloody stools. Diarrhea can be either acute (short-term) or chronic (long-term). The acute form, which lasts less than 4 weeks, is usually related to a bacterial, viral, or parasitic infection. Chronic diarrhea lasts more than 4 weeks and is usually related to functional disorders like irritable bowel syndrome or inflammatory bowel diseases like celiac disease.

Children can have acute or chronic forms of diarrhea. Causes include bacteria, viruses, parasites, medications, functional disorders, and food sensitivities. Infection with the rotavirus is the most common cause of acute childhood diarrhea. Rotavirus diarrhea usually resolves in 3 to 9 days. Diarrhea can be dangerous in newborns and infants. In small children, severe diarrhea lasting just a day or two can lead to dehydration. Because a child can die from dehydration within a few days, the main treatment for diarrhea in children is rehydration.

What is dehydration?
General signs of dehydration include:

• thirst
• less frequent urination
• dry skin
• fatigue
• light-headedness
• dark colored urine
• Signs of dehydration in children include
• dry mouth and tongue
• no tears when crying
• no wet diapers for 3 hours or more
• sunken abdomen, eyes, or cheeks
• high fever
• listlessness or irritability
• skin that does not flatten when pinched and released

When should a doctor be consulted?
Although usually not harmful, diarrhea can become dangerous or signal a more serious problem. You should see the doctor if any of the following is true:

• You have diarrhea for more than 3 days.
• You have severe pain in the abdomen or rectum.
• You have a fever of 102 degrees Fahrenheit or higher.
• You see blood in your stool or have black, tarry stools.
• You have signs of dehydration.
• If your child has diarrhea, do not hesitate to call the doctor for advice. Diarrhea can be dangerous in children if too much fluid is lost and not replaced quickly.