What is diarrhea?

Diarrhea is when your stools are loose and watery. You may also need to go to the bathroom more often. Diarrhea is a common problem. It may last 1 or 2 days and go away on its own. If it lasts more than 4 days, it may mean you have a more serious problem.

Diarrhea may be either:

Short-term (acute). This type lasts 1 or 2 days and then goes away. It may be caused by food or water that was made unsafe by bacteria. Or it may happen if you get sick from a virus or a food toxin.
Long-term (chronic). This type lasts several weeks. It may be caused by another health problem such as irritable bowel syndrome. It can also be caused by an intestinal disease such as Crohn’s disease or celiac disease. Some infections, such as parasites, can cause chronic diarrhea.

What causes diarrhea?

Diarrhea may be caused by many things, including:

A bacterial infection
A virus
Food poisoning
Trouble digesting certain things (food intolerance)
Food allergy such as to milk
Parasites that enter the body through food or water
A reaction to medicines
An intestinal disease, such as inflammatory bowel disease
A problem with how your stomach and bowels work (functional bowel disorder), such as irritable bowel syndrome
A result of surgery on the stomach or gallbladder
Recent antibiotic use
Metabolic problems such as thyroid conditions
Other less common reasons such as damage from radiation treatments or tumors that make too many hormones

Many people get traveler's diarrhea. This happens when you have food or water that is not safe because of bacteria, parasites, and even food poisoning.

Severe diarrhea may mean you have a serious disease. See your healthcare provider if your symptoms don’t go away or if they keep you from doing your daily activities. It may be hard to find out what is causing your diarrhea.

What are the symptoms linked with diarrhea?

Each person’s symptoms may vary. Symptoms associated with diarrhea may include:

Belly (abdominal) cramps
Stomach pain
Swelling (bloating)
Upset stomach (nausea or vomiting)
Urgent need to go to the bathroom
Fever
Bloody stools
Loss of body fluids (dehydration)
Leaking stool and not being able to control your bowels (incontinence)

Dehydration is a serious side effect of diarrhea. Symptoms include:

Feeling thirsty
Not urinating as often
Having dry skin as well as a dry mouth and nostrils (mucous membranes)
Feeling very tired
Feeling that you may pass out or faint (lightheaded)
Headaches
Fast heart rate

Diarrhea symptoms may look like other health problems. Bloody diarrhea is always a concern. Always see your healthcare provider to be sure. Tell the healthcare provider about any bleeding, fever, or vomiting.

How is diarrhea diagnosed?

To determine if there is a cause of diarrhea, your healthcare provider will give you a physical exam and ask about your past health. You may also have lab tests to check your blood and urine.

Other tests may include:

Stool studies, including culture and other tests. This test checks for any abnormal bacteria or parasites in your digestive tract that may cause diarrhea and other problems. To do this test, a small stool sample is taken and sent to a lab.

Sigmoidoscopy. This test lets your healthcare provider check the inside of part of your large intestine. It helps tell what is causing diarrhea. A short, flexible, lighted tube (sigmoidoscope) is put into your intestine through the rectum. This tube blows air into your intestine to make it swell. This makes it easier to see inside. A small tissue sample (biopsy) can be taken if needed.

Colonoscopy. This diagnostic procedure looks at the full length of your large intestine. It can help check for any abnormal growths, tissue that is red or swollen, sores (ulcers), or bleeding. A long, flexible, lighted tube (colonoscope) is put into your rectum up into the colon. This tube lets your healthcare provider see the lining of your colon and take out a small tissue sample (biopsy) to test it. They can also treat some problems that may be found.

Imaging tests. These tests can see if there are any problems with the way your organs are formed (structural abnormalities).

Fasting tests and oral food challenges. These tests show if you are unable to digest certain foods (food intolerance). They can also tell if certain foods bring on an immune system reaction (food allergy).
Blood tests. These can look for metabolic problems like thyroid disease, anemia (low blood count), low vitamin levels that can mean poor absorption, and celiac disease, among other things.

How is diarrhea treated?

Treatment depends on your diagnosis. The severity of your symptoms, age, and general health may also impact treatment decisions.

In most cases, you will need to replace the fluids you have lost. If dehydration is severe, the best replacement is called an oral rehydration solution instead of fruit juice or sports drinks. You may also need a medicine that fights infection (antibiotic) if a bacterial infection is causing your diarrhea. Antidiarrhea medicines are commonly used, but they should not be used if you have bloody diarrhea or diarrhea with a fever.

What are possible complications of diarrhea?

If your diarrhea is severe, you are at risk for dehydration. Severe dehydration can lead to organ damage, shock, fainting (loss of consciousness) or coma, and even death.

What can I do to prevent diarrhea?

Having good personal habits can keep you from getting diarrhea caused by bacteria or a virus. They include:

Wash your hands often.
Use alcohol-based sanitizers.
Eat foods that have been cleaned and cooked in a safe way.
Don't eat or drink any foods or liquids that may have been infected with a bacteria or virus.

When you are traveling, check that anything you eat and drink is safe. This is even more important if you travel to developing countries.

Travel safety tips for water and other liquids include:

Not drinking tap water or using it to brush your teeth
Not using ice made from tap water
Not drinking milk or milk items that have not gone through a process to kill certain bacteria (pasteurization)

Travel safety tips for food include:

Don't eat any fresh or raw fruits and vegetables unless you wash and peel them yourself.
Make sure all meat and fish have been cooked to a safe minimum internal temperature.
Don't eat raw or rare-cooked meat or fish.
Don't eat food from street vendors or food trucks.

Living with diarrhea

In most cases, diarrhea is a short-term problem. It usually only lasts for a few days. Take plenty of liquids when you’re having a bout of diarrhea.

Some health problems can make diarrhea last longer or keep coming back. These include inflammatory bowel disease and irritable bowel syndrome. If another health problem is causing your diarrhea, follow your healthcare provider’s advice for treating that problem.

When should I call my healthcare provider?

Call your healthcare provider or seek medical care if you have:

Diarrhea more often
A greater amount of diarrhea
Symptoms of dehydration—feeling thirsty, tired, or dizzy or having less urine or a dry mouth
Bloody diarrhea or black and tarry stools, a fever, or are vomiting

Key points about diarrhea

Diarrhea is when your stools are loose and watery.
You may also need to go to the bathroom more often.
Short-term (acute) diarrhea lasts 1 or 2 days.
Long-term (chronic) diarrhea may last several weeks.
Diarrhea symptoms may include belly cramps and an urgent need to go to the bathroom.
Loss of fluids (dehydration) is one of the more serious side effects.
Treatment usually involves replacing lost fluids and treating the cause if known.
You may need an antibiotic medicine if a bacterial infection is the cause.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

Know the reason for your visit and what you want to happen.
Before your visit, write down questions you want answered.
Bring someone with you to help you ask questions and remember what your provider tells you.
At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are and when they should be reported.
Ask if your condition can be treated in other ways.
Know why a test or procedure is recommended and what the results could mean.
Know what to expect if you do not take the medicine or have the test or procedure.
If you have a follow-up appointment, write down the date, time, and purpose for that visit.
Know how to contact your provider if you have questions, especially after office hours and on weekends and holidays.