Overview illustration of Diarrhea

Diarrhea Overview

Most people have had diarrhea—characterized by loose, watery stool during frequent bowel movements—at one point or another. It's usually caused by a virus or contaminated food, but less frequently it can be due to inflammatory bowel disease or irritable bowel syndrome.

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Diarrhea is when you frequently pass loose and watery stools. The most common cause is a virus, although diarrhea that persists can indicate another health condition like irritable bowel syndrome (IBS). Most cases of diarrhea go away on their own, but others may need treatment with medications or even surgery. You can also prevent certain types of diarrhea with lifestyle measures.

What Is It?

Diarrhea is usually recognizable by soft and watery stools. You may also find yourself going to the bathroom more often than normal. Some experts say you have diarrhea when you produce watery stools at least three times a day, but this can vary greatly between individuals. Acute diarrhea usually lasts just a day or two and goes away on its own. Diarrhea that lasts longer may be a sign of another underlying medical condition and, in some cases, can be life-threatening. According to one estimate, there are 179 million cases of diarrhea in the U.S. each year with an adult, on average, having diarrhea once annually and children twice. Diarrhea can affect anyone but children are more prone to the condition and more prone to complications.


Experts generally point to three types of diarrhea, based largely on how long the symptoms last:

  1. Acute diarrhea is the most common type of diarrhea, it's also the shortest, lasting typically one to two days, and usually goes away on its own.
  2. Persistent diarrhea lasts longer than two weeks but less than four.
  3. Chronic diarrhea lasts four or more weeks. Symptoms may be constant, or they may go away then come back again. If you have diarrhea that doesn't go away, talk to your doctor about possible causes.


While the hallmarks of diarrhea are the loose and watery stools, you may also have other symptoms such as:

  • Pain or cramping in your abdomen
  • Bloating
  • Nausea
  • Needing to go to the bathroom urgently
  • Blood or mucus in your stool
  • Fever and chills

You should see a doctor if you have black, tarry or bloody stools, severe pain in your abdomen or rectum, or a fever of 102 degrees Fahrenheit or above.

One of the most serious complications of diarrhea, especially diarrhea that lasts longer than one or two days, is dehydration. Symptoms of dehydration include feeling thirsty all the time, urinating less than usual or producing dark urine, a dry mouth, skin that doesn't bounce back when you pinch it, sunken eyes or cheeks, fainting or feeling lightheaded, nausea and vomiting, and not producing tears when you cry. You may also have a rapid heartbeat and headaches.

Diarrhea can also cause malabsorption, which is when your body doesn't get enough nutrients from food. Symptoms of malabsorption include bloating and gas, weight loss, appetite changes and stools that are not only loose but are also greasy and smell bad. Severe dehydration and malabsorption are also times to get medical help.


The most common cause of acute diarrhea is a virus, a condition also known as "viral gastroenteritis." In adults, the most likely culprit is the Norwalk virus (circulating widely on cruise ships) and, in children, rotavirus can also cause diarrhea, as can different bacteria and parasites. Typically, these are passed on through contaminated food or water often when you're traveling to other countries (called traveler's diarrhea).

Intolerance to certain kinds of food can also cause diarrhea. This includes lactose, (a sugar found in milk and other dairy products), sorbitol, mannitol, (artificial sweeteners often used in gum), and fructose, (a sugar in fruits and honey).

Medications, including many antibiotics, can cause diarrhea, as can certain medical conditions including Crohn's disease, ulcerative colitis, celiac disease, irritable bowel syndrome and inflammatory bowel disease. Less commonly, abdominal surgery, colon cancer or polyps and radiation therapy can result in diarrhea.


Acute diarrhea often goes away on its own without needing a diagnosis. For other cases, doctors start by asking questions about how long you've had the problem, if you've traveled recently, what your stools look like and if you have any personal or family history of bowel disorders. Your doctor may also listen to your abdomen with a stethoscope or do a digital rectal exam which means using his or her gloved finger to check your rectum.

If your doctor suspects food intolerance, he or she may administer a breath test which can determine if you're intolerant to fructose or lactose. Or you may be asked to cut out certain foods (like wheat) for a period of time to see if your diarrhea resolves (this is called a fasting test). Blood tests can tell you if have certain underlying conditions like a thyroid disorder and stool tests can detect some pathogens.

If none of these tests find the reason, there are imaging tests like a colonoscopy, a flexible sigmoidoscopy, or upper gastrointestinal endoscopy to investigate the inside of your digestive system.


Acute diarrhea can be managed at home by watching what you eat and drink. Many people find relief following the bland BRAT (bananas, white rice, applesauce and white-bread toast) and staying away from caffeine, alcohol, greasy, fatty or fried foods, dairy products, and spicy food.

Over-the-counter bismuth subsalicylate (Pepto-Bismol or Kaopectate) can also help, as can loperamide (Immodium), which slows down your bowel. Don't take antidiarrheal drugs if you have any signs of a bacterial infection like bloody stool or a fever. Health professionals also prescribe antibiotics for some cases of diarrheas as well as drugs to treat specific underlying illnesses. Some people take probiotics, which are easily available at grocery stores and pharmacies, but check with your doctor before trying one of these products.

If you do get diarrhea, prevent dehydration by drinking plenty of fluids, especially ones with electrolytes, such as fruit juice, sports drinks, soup broths and soft drinks without caffeine. People at higher risk for dehydration should look for or make rehydration solutions that contain glucose and electrolytes.


You can prevent some types of diarrhea, such as traveler's diarrhea. Basic hygiene measures will help. This means washing your hands, especially before and after handling food, as well as after going to the bathroom or sneezing or coughing. Keep the lather going for at least 20 seconds before rinsing. If there's no soap-and-water available, use a hand sanitizer containing at least 60% alcohol.

You can also lower your risk of foodborne illness by storing food at the recommended temperature, tossing any rotting items and cooking foods thoroughly. Wash any raw fruits or vegetables before eating them as they can contain Salmonella and other bacteria that cause food poisoning.

Many of these same measures can help prevent traveler's diarrhea. When out of the U.S., eat only well-cooked foods and avoid anything raw (unless it's a banana or something else you can peel). Unless you're having coffee or tea made from boiled water, drink only bottled beverages— not tap water or ice. Use bottled water when you brush your teeth and don't open your mouth in the shower. Sometimes doctors will prescribe antibiotics as a preventative measure if you are going to a developing country for any length of time. And before you go, check the Centers for Disease Control and Prevention website to see if there are any warnings pertaining to your intended destination. Infants can get vaccinated against rotavirus, which is the most common cause of diarrhea in children.

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