Diarrhea
 National Digestive Diseases Information Clearinghouse 

U.S. Department 

of Health and 

Human Services 

NATIONAL 

INSTITUTES 

OF HEALTH 

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. 

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. 

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 

2	� Diarrhea 
 

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. 

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. 

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. 

3	� Diarrhea 
 

 

 

 

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. 

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. 

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. 

4	� Diarrhea 
 

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. 

5	� Diarrhea 
 

 

 

 

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. 

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. 

6	� Diarrhea 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For More Information 

American College of Gastroenterology 

P.O. Box 342260 

Bethesda, MD 20827–2260 

Phone: 301–263–9000 

Internet: www.acg.gi.org 

Centers for Disease Control and Prevention 

1600 Clifton Road 

Atlanta, GA 30333 

Phone: 1–800–CDC–INFO 

(1–800–232–4636) 

TTY: 1–888–232–6348 

Email: cdcinfo@cdc.gov 

Internet: www.cdc.gov 

International Foundation for Functional 

Gastrointestinal Disorders 

P.O. Box 170864 

Milwaukee, WI 53217–8076 

Phone: 1–888–964–2001 or 414–964–1799 

Fax: 414–964–7176 

Email: iffgd@iffgd.org 

Internet: www.iffgd.org 

North American Society for Pediatric 

Gastroenterology, Hepatology and Nutrition 

P.O. Box 6 

Flourtown, PA 19031 

Phone: 215–233–0808 

Fax: 215–233–3918 

Email: naspghan@naspghan.org 

Internet: www.naspghan.org 

Acknowledgments 

Publications produced by the Clearinghouse 

are carefully reviewed by both NIDDK 

scientists and outside experts. This publication was reviewed by Mark Donowitz, M.D., 

Johns Hopkins University School of Medicine, and John S. Fordtran, M.D., Baylor 

University Medical Center. 

You may also find additional information about this 

topic by visiting MedlinePlus at www.medlineplus.gov. 

This publication may contain information about 

medications. When prepared, this publication 

included the most current information available. 

For updates or for questions about any medications, 

contact the U.S. Food and Drug Administration tollfree at 1–888–INFO–FDA (1–888–463–6332) or visit 

www.fda.gov. Consult your health care provider for 

more information. 

The U.S. Government does not endorse or favor any 

specific commercial product or company. Trade, 

proprietary, or company names appearing in this 

document are used only because they are considered 

necessary in the context of the information provided. 

If a product is not mentioned, the omission does not 

mean or imply that the product is unsatisfactory. 

7 Diarrhea 
 

 

 

 

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The National Digestive Diseases Information 

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and Kidney Diseases (NIDDK). The 

NIDDK is part of the National Institutes of 

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www.digestive.niddk.nih.gov. 

U.S. DEPARTMENT OF HEALTH 

AND HUMAN SERVICES 

National Institutes of Health 

NIH Publication No. 11–2749 

January 2011 

The NIDDK prints on recycled paper with bio-based ink.