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. 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.
Dehydration is discussed below. People of all ages can get diarrhea. The average adult has a bout of
diarrhea about four times a year.
What Causes Diarrhea?
Diarrhea may be caused by a temporary problem, like an infection, or a
chronic problem, like an intestinal disease. 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 a 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.
Some people develop diarrhea after stomach surgery or removal of the
gallbladder. The reason may be a change in how quickly food moves through the
digestive system after stomach surgery or an increase in bile in the colon
that can occur after gallbladder surgery. In many cases, the cause of diarrhea cannot be found. As long as diarrhea
goes away on its own, an extensive search for the cause is not usually
necessary. People who visit foreign countries are at risk for traveler's diarrhea,
which is caused by eating food or drinking water contaminated with bacteria,
viruses, or, sometimes, parasites. Traveler's diarrhea is a particular problem
for people visiting developing countries. Visitors to the United States,
Canada, most European countries, Japan, Australia, and New Zealand do not face
much risk for traveler's diarrhea.
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 or chronic. The acute form, which lasts less
than 3 weeks, is usually related to a bacterial, viral, or parasitic
infection. Chronic diarrhea lasts more than 3 weeks and is usually related to
functional disorders like irritable bowel syndrome or diseases like celiac
disease or inflammatory bowel disease.
Diarrhea in Children
Children can have acute (short-term) or chronic (long-term) 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 5 to 8 days. Medications to treat diarrhea in adults can be dangerous to children and
should be given only under a doctor's guidance. 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. Rehydration is discussed below. Take your child to the doctor if any of the following symptoms appear:
- Stools containing blood or pus, or black stools
- Temperature above 101.4 degrees Fahrenheit
- No improvement after 24 hours
- Signs of dehydration (see below)
What Is Dehydration?
General signs of dehydration include:
- Less frequent urination
- Dry skin
- 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
If you suspect that you or your child is dehydrated, call the doctor
immediately. Severe dehydration may require hospitalization.
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:
- 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
What Tests Might the Doctor Do?
Diagnostic tests to find the cause of diarrhea include the following:
- Medical history and physical examination. The doctor will need to
know about your eating habits and medication use and will examine you for
signs of illness.
- Stool culture. Lab technicians analyze a sample of stool to check
for bacteria, parasites, or other signs of disease or infection.
- Blood tests. Blood tests can be helpful in ruling out certain
- Fasting tests. To find out if a food intolerance or allergy is
causing the diarrhea, the doctor may ask you to avoid lactose (found in
milk products), carbohydrates, wheat, or other foods to see whether the
diarrhea responds to a change in diet.
- Sigmoidoscopy. For this test, the doctor uses a special
instrument to look at the inside of the rectum and lower part of the
- Colonoscopy. This test is similar to sigmoidoscopy, but the
doctor looks at the entire colon.
What Is the Treatment? In most cases, replacing lost fluid to prevent dehydration is the only
treatment necessary. (See "Preventing Dehydration" below.) Medicines
that stop diarrhea may be helpful in some cases, but they are not recommended
for people whose diarrhea is from a bacterial infection or parasite--stopping
the diarrhea traps the organism in the intestines, prolonging the problem.
Instead, doctors usually prescribe antibiotics. Viral causes are either
treated with medication or left to run their course, depending on the severity
and type of the virus. Preventing Dehydration
Dehydration occurs when the body has lost too much fluid and electrolytes
(the salts potassium and sodium). The fluid and electrolytes lost during
diarrhea need to be replaced promptly--the body cannot function properly
without them. Dehydration is particularly dangerous for children, who can die
from it within a matter of days. Although water is extremely important in preventing dehydration, it does
not contain electrolytes. To maintain electrolyte levels, you could have broth
or soups, which contain sodium, and fruit juices, soft fruits, or vegetables,
which contain potassium. For children, doctors often recommend a special rehydration solution that
contains the nutrients they need. You can buy this solution in the grocery
store without a prescription. Examples include Pedialyte, Ceralyte, and
Infalyte. Tips About Food
Until diarrhea subsides, try to avoid milk products and foods that are
greasy, high-fiber, or very sweet. These foods tend to aggravate diarrhea. As you improve, you can add soft, bland foods to your diet, including
bananas, plain rice, boiled potatoes, toast, crackers, cooked carrots, and
baked chicken without the skin or fat. For children, the pediatrician may
recommend what is called the BRAT diet: bananas, rice, applesauce, and toast.
Preventing Traveler's Diarrhea Traveler's diarrhea happens when you consume food or water contaminated
with bacteria, viruses, or parasites. You can take the following precautions
to prevent traveler's diarrhea when you go abroad:
- Do not drink any tap water, not even when brushing your teeth.
- Do not drink unpasteurized milk or dairy products.
- Do not use ice made from tap water.
- Avoid all raw fruits and vegetables (including lettuce and fruit salad)
unless they can be peeled and you peel them yourself.
- Do not eat raw or rare meat and fish.
- Do not eat meat or shellfish that is not hot when served to you.
- Do not eat food from street vendors.
You can safely drink bottled water (if you are the one to break the seal),
carbonated soft drinks, and hot drinks like coffee or tea. Depending on where you are going and how long you are staying, your doctor
may recommend that you take antibiotics before leaving to protect you from
Points To Remember
- Diarrhea is a common problem that usually resolves on its own.
- Diarrhea is dangerous if a person becomes dehydrated.
- Causes include viral, bacterial, or parasitic infections; food
intolerance; reactions to medicine; intestinal diseases; and functional
- Treatment involves replacing lost fluids and electrolytes. Depending on
the cause of the problem, a person might also need medication to stop the
diarrhea or treat an infection. Children may need an oral rehydration
solution to replace lost fluids and electrolytes.
- Call the doctor if a person with diarrhea has severe pain in the abdomen
or rectum, a fever of 102 degrees Fahrenheit or higher, blood in the
stool, signs of dehydration, or diarrhea for more than 3 days.
Last Reviewed: January