What is diarrhea?
Diarrhea is loose, watery stools. Having diarrhea means passing loose
stools three or more times a day. Acute diarrhea is a common problem
that usually lasts 1 or 2 days and goes away on its own.
Diarrhea lasting more than 2 days may be a sign of a more serious
problem. Chronic diarrhea—diarrhea that lasts at least 4 weeks—may be a
symptom of a chronic disease. Chronic diarrhea symptoms may be continual
or they may come and go.
Diarrhea of any duration may cause dehydration, which means the body
lacks enough fluid and electrolytes—chemicals in salts, including
sodium, potassium, and chloride—to function properly. Loose stools
contain more fluid and electrolytes and weigh more than solid stools.
People of all ages can get diarrhea. In the United States, adults average one bout of acute diarrhea each year,
1 and young children have an average of two episodes of acute diarrhea each year.
2
1DuPont HL, Practice Parameters
Committee of the American College of Gastroenterology. Guidelines on
acute infectious diarrhea in adults. The American Journal of Gastroenterology. 1997;92(11):1962–1975.
2Ramaswamy K, Jacobson K. Infectious diarrhea in children. Gastroenterology Clinics of North America. 2001;30(3):611–624.
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What causes diarrhea?
Acute diarrhea is usually caused by a bacterial, viral, or parasitic
infection. Chronic diarrhea is usually related to a functional disorder
such as irritable bowel syndrome or an intestinal disease such as
Crohn’s disease.
The most common causes of diarrhea include the following:
- Bacterial infections. Several types of bacteria consumed through contaminated food or water can cause diarrhea. Common culprits include Campylobacter, Salmonella, Shigella, and Escherichia coli (E. coli).
- Viral infections. Many viruses cause diarrhea,
including rotavirus, norovirus, cytomegalovirus, herpes simplex virus,
and viral hepatitis. Infection with the rotavirus is the most common
cause of acute diarrhea in children. Rotavirus diarrhea usually resolves
in 3 to 7 days but can cause problems digesting lactose for up to a
month or longer.
- 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.
- Functional bowel disorders. Diarrhea can be a symptom of irritable bowel syndrome.
- Intestinal diseases. Inflammatory bowel disease, ulcerative colitis, Crohn’s disease, and celiac disease often lead to diarrhea.
- Food intolerances and sensitivities. Some
people have difficulty digesting certain ingredients, such as lactose,
the sugar found in milk and milk products. Some people may have diarrhea
if they eat certain types of sugar substitutes in excessive quantities.
- Reaction to medicines. Antibiotics, cancer drugs, and antacids containing magnesium can all cause diarrhea.
Some people develop diarrhea after stomach surgery, which may cause food to move through the digestive system more quickly.
People who visit certain foreign countries are at risk for traveler’s
diarrhea, which is caused by eating food or drinking water contaminated
with bacteria, viruses, or parasites. Traveler’s diarrhea can be a
problem for people traveling to developing countries in Africa, Asia,
Latin America, and the Caribbean. Visitors to Canada, most European
countries, Japan, Australia, and New Zealand do not face much risk for
traveler’s diarrhea.
In many cases, the cause of diarrhea cannot be found. As long as
diarrhea goes away on its own within 1 to 2 days, finding the cause is
not usually necessary.
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What other symptoms accompany diarrhea?
Diarrhea may be accompanied by cramping, abdominal pain, nausea, an
urgent need to use the bathroom, or loss of bowel control. Some
infections that cause diarrhea can also cause a fever and chills or
bloody stools.
Dehydration
Diarrhea can cause dehydration. Loss of electrolytes through
dehydration affects the amount of water in the body, muscle activity,
and other important functions.
Dehydration is particularly dangerous in children, older adults, and
people with weakened immune systems. Dehydration must be treated
promptly to avoid serious health problems, such as organ damage, shock,
or coma—a sleeplike state in which a person is not conscious.
Signs of dehydration in adults include
- thirst
- less frequent urination than usual
- dark-colored urine
- dry skin
- fatigue
- dizziness
- light-headedness
Signs of dehydration in infants and young children include
- dry mouth and tongue
- no tears when crying
- no wet diapers for 3 hours or more
- sunken eyes, cheeks, or soft spot in the skull
- high fever
- listlessness or irritability
Also, when people are dehydrated, their skin does not flatten back to normal right away after being gently pinched and released.
Anyone with signs of dehydration should see a health care provider immediately. Severe dehydration may require hospitalization.
Although drinking plenty of water is important in preventing
dehydration, water does not contain electrolytes. Adults can prevent
dehydration by also drinking liquids that contain electrolytes, such as
fruit juices, sports drinks, caffeine-free soft drinks, and broths.
Children with diarrhea should be given oral rehydration solutions such
as Pedialyte, Naturalyte, Infalyte, and CeraLyte to prevent dehydration.
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When should adults with diarrhea see a health care provider?
Adults with any of the following symptoms should see a health care provider:
- signs of dehydration
- diarrhea for more than 2 days
- severe pain in the abdomen or rectum
- a fever of 102 degrees or higher
- stools containing blood or pus
- stools that are black and tarry
Diarrhea is not usually harmful, but it can become dangerous or signal a more serious problem.
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When should children with diarrhea see a health care provider?
Children with any of the following symptoms should see a health care provider:
- signs of dehydration
- diarrhea for more than 24 hours
- a fever of 102 degrees or higher
- stools containing blood or pus
- stools that are black and tarry
If children have diarrhea, parents or caregivers should not hesitate
to call a health care provider for advice. Diarrhea is especially
dangerous in newborns and infants, leading to severe dehydration in just
a day or two. Children can die from dehydration within a day.
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How is the cause of diarrhea diagnosed?
If acute diarrhea lasts 2 days or less, diagnostic tests are usually
not necessary. If diarrhea lasts longer or is accompanied by symptoms
such as fever or bloody stools, a doctor may perform tests to determine
the cause.
Diagnostic tests to find the cause of diarrhea may include the following:
- Medical history and physical examination. The
doctor will ask about eating habits and medication use and will perform a
physical examination to look for signs of illness.
- Stool culture. A sample of stool is analyzed in a laboratory to check for bacteria, parasites, or other signs of disease and infection.
- Blood tests. Blood tests can be helpful in ruling out certain diseases.
- Fasting tests. To find out if a food
intolerance or allergy is causing the diarrhea, the doctor may ask a
person to avoid foods with lactose, carbohydrates, wheat, or other
ingredients to see whether the diarrhea responds to a change in diet.
- Sigmoidoscopy or colonoscopy. These tests may
be used to look for signs of intestinal diseases that cause chronic
diarrhea. For sigmoidoscopy, the doctor uses a thin, flexible, lighted
tube with a lens on the end to look at the inside of the rectum and
lower part of the colon. Colonoscopy is similar to sigmoidoscopy, but it
allows the doctor to view the entire colon.
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How is diarrhea treated?
In most cases of diarrhea, the only treatment necessary is replacing lost fluids and electrolytes to prevent dehydration.
Over-the-counter medicines such as loperamide (Imodium) and bismuth
subsalicylate (Pepto-Bismol and Kaopectate) may help stop diarrhea in
adults. However, people with bloody diarrhea—a sign of bacterial or
parasitic infection—should not use these medicines. If diarrhea is
caused by bacteria or parasites, over-the-counter medicines may prolong
the problem, so doctors usually prescribe antibiotics instead.
Medications to treat diarrhea in adults can be dangerous for infants
and children and should only be given with a doctor’s guidance.
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Eating, Diet, and Nutrition
Until diarrhea subsides, avoiding caffeine and foods that are greasy,
high in fiber, or sweet may lessen symptoms. These foods can aggravate
diarrhea. Some people also have problems digesting lactose during or
after a bout of diarrhea. Yogurt, which has less lactose than milk, is
often better tolerated. Yogurt with active, live bacterial cultures may
even help people recover from diarrhea more quickly.
As symptoms improve, soft, bland foods can be added to the diet,
including bananas, plain rice, boiled potatoes, toast, crackers, cooked
carrots, and baked chicken without the skin or fat. For children, the
health care provider may also recommend a bland diet. Once the diarrhea
stops, the health care provider will likely encourage children to return
to a normal and healthy diet if it can be tolerated. Infants with
diarrhea should be given breast milk or full-strength formula as usual,
along with oral rehydration solutions. Some children recovering from
viral diarrheas have problems digesting lactose for up to a month or
more.
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Can diarrhea be prevented?
Two types of diarrhea can be prevented—rotavirus diarrhea and traveler’s diarrhea.
Rotavirus Diarrhea
Two oral vaccines have been approved by the U.S. Food and Drug
Administration to protect children from rotavirus infections: rotavirus
vaccine, live, oral, pentavalent (RotaTeq); and rotavirus vaccine, live,
oral (Rotarix). RotaTeq is given to infants in three doses at 2, 4, and
6 months of age. Rotarix is given in two doses. The first dose is given
when infants are 6 weeks old, and the second is given at least 4 weeks
later but before infants are 24 weeks old.
Parents of infants should discuss rotavirus vaccination with a health
care provider. For more information, parents can visit the Centers for
Disease Control and Prevention rotavirus vaccination webpage at
www.cdc.gov/vaccines/vpd-vac/rotavirus.
Traveler’s Diarrhea
To prevent traveler’s diarrhea, people traveling from the United States to developing countries should avoid
- drinking tap water, using tap water to brush their teeth, or using ice made from tap water
- drinking unpasteurized milk or milk products
- eating raw fruits and vegetables, including lettuce and fruit salads, unless they peel the fruits or vegetables themselves
- eating raw or rare meat and fish
- eating meat or shellfish that is not hot when served
- eating food from street vendors
Travelers can drink bottled water, soft drinks, and hot drinks such as coffee or tea.
People concerned about traveler’s diarrhea should talk with a health
care provider before traveling. The health care provider may recommend
that travelers bring medicine with them in case they develop diarrhea
during their trip. Health care providers may advise some
people—especially people with weakened immune systems—to take
antibiotics before and during a trip to help prevent traveler’s
diarrhea. Early treatment with antibiotics can shorten a bout of
traveler’s diarrhea.
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Points to Remember
- Diarrhea is loose, watery stools. Having diarrhea means passing loose stools three or more times a day.
- Diarrhea is a common problem that usually goes away on its own.
- The most common causes of diarrhea include bacterial, viral, and
parasitic infections; functional bowel disorders; intestinal diseases;
food intolerances and sensitivities; and reactions to medicines.
- Diarrhea can cause dehydration, which is particularly dangerous
in children, older adults, and people with weakened immune systems.
- Treatment involves replacing lost fluids and electrolytes.
Depending on the cause of the problem, medication may also be needed to
stop the diarrhea or treat an infection.
- Children with diarrhea should be given oral rehydration solutions to replace lost fluids and electrolytes.
- Adults with any of the following symptoms should see a health
care provider: signs of dehydration, diarrhea for more than 2 days,
severe pain in the abdomen or rectum, a fever of 102 degrees or higher,
stools containing blood or pus, or stools that are black and tarry.
- Children with any of the following symptoms should see a health
care provider: signs of dehydration, diarrhea for more than 24 hours, a
fever of 102 degrees or higher, stools containing blood or pus, or
stools that are black and tarry.
- People can take steps to prevent two types of diarrhea—rotavirus diarrhea and traveler’s diarrhea.
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Hope through Research
The Division of Digestive Diseases and Nutrition at the National
Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) supports
basic and clinical research into gastrointestinal diseases, including
diarrhea. Among other areas, researchers are studying
- vaccines to prevent diarrhea caused by viruses
- new treatments for diarrhea, such as zinc supplements and probiotics
- medicines to prevent and treat traveler’s diarrhea
Participants in clinical trials can play a more active role in their
own health care, gain access to new research treatments before they are
widely available, and help others by contributing to medical research.
For information about current studies, visit
www.ClinicalTrials.gov.
