What Is Diarrhea? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Diarrhea is a common ailment that most people experience from time to time. It is characterized by the passing of loose, watery stools and is often accompanied by abdominal pain and cramping.

Diarrhea typically clears up on its own within a few days, but severe or chronic diarrhea that lasts for weeks can be a sign of a serious health problem that needs medical attention, according to the Mayo Clinic.

The main and most recognizable symptom of diarrhea is loose, watery stools that pass three or more times a day, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diarrhea may also cause the following symptoms:

• Pain or cramping in the abdomen
• An urgent need to go to the bathroom
• Nausea
• Loss of control of bowel movements

If diarrhea is caused by an infection or inflammation, people may also experience:

• Bloody stools
• Vomiting
• Fever and chills
• Light-headedness and dizziness

Diarrhea may also cause dehydration and malabsorption, each of which has its own symptoms.

Signs of dehydration include thirst, less-frequent urination, dark-colored urine, dry mouth, feeling tired, sunken eyes or cheeks, light-headedness or fainting, and decreased skin turgor (when the skin is pinched and released, it does not flatten back to normal right away).

Symptoms of malabsorption include bloating, gas, changes in appetite, weight loss, and loose, greasy, foul-smelling bowel movements, according to the NIDDK. (1)

Learn More About Symptoms of Diarrhea

Diarrhea can be caused by a number of factors. The most common causes of diarrhea include:

Infection Three types of infections cause diarrhea.

• Viral infections, including norovirus and rotavirus
• Bacterial infections, which can come from contaminated food or water. Common bacteria that cause diarrhea include Campylobacter, Escherichia coli (E. coli), salmonella, and Shigella.
• Parasitic infections, in which parasites enter your body through food or water. Common parasites found in the United States that cause diarrhea include Cryptosporidium and Giardia lamblia.

Traveler’s diarrhea This type of infectious diarrhea is caused by eating food or drinking water contaminated with bacteria, viruses, or parasites while traveling abroad, usually in a developing country. Traveler's diarrhea is usually acute (short-lasting), but certain parasites may cause your diarrhea to last longer.

Side effect of medication Many medications may cause diarrhea, including antibiotics, antacids, oral diabetes medication, and cancer drugs. If you believe your medication may be the cause of your diarrhea, talk to your healthcare provider, who may alter the dose or switch you to another medication.

Food allergies and intolerances Sometimes diarrhea is caused by an allergy to certain foods, such as dairy, soy, eggs, or seafood. In these cases, diarrhea is often chronic.

Lactose intolerance is a common condition that can cause diarrhea and other gastrointestinal symptoms after you eat foods or drink beverages containing lactose, the sugar found in milk or milk products like ice cream.

Digestive disorders Diarrhea may be a sign of a more serious health problem, such as a disorder of the digestive system. While the most common reason is irritable bowel syndrome (IBS), other causes can include inflammatory bowel diseases (IBD) like Crohn’s disease or ulcerative colitis, and celiac disease.

Diarrhea may also be a sign of bacterial overgrowth in the small intestine. (1)

Most people who experience diarrhea do not go on to receive an official diagnosis, since their symptoms clear up within four days, according to NIDDK. People who experience persistent or chronic diarrhea should seek medical attention so that a doctor can diagnose the cause and prescribe treatment, if necessary.

Tests for diarrhea may include blood tests, stool tests, a breath test for lactose intolerance, upper endoscopy (looking at your stomach and upper small intestine using a tiny camera), and colonoscopy or flexible sigmoidoscopy (doing the same in your lower digestive system), according to the Mayo Clinic. (2)

Diarrhea can either be acute (short-lasting) or chronic, meaning it lasts longer. Usually, acute diarrhea will clear up on its own in a few days. But sometimes acute diarrhea becomes persistent, meaning that it lasts longer than two weeks but less than four weeks, according to the NIDDK.

Chronic diarrhea lasts for longer than four weeks, and may indicate a serious health problem. Potential causes of chronic diarrhea include infection, food allergies and intolerances, digestive disorders, medications, and abdominal surgery.

How to Prevent Diarrhea

While diarrhea may be a sign of an underlying health condition, there are steps you can take to avoid some of the causes of diarrhea.

One of the most important things you can do to prevent diarrhea is to wash your hands frequently. Be sure to wash your hands after using the bathroom, before preparing or eating food, before and after caring for someone who is ill, after touching garbage, and after touching an animal, animal feed, or animal waste.

If soap and clean water are not available, use an alcohol-based hand sanitizer that contains at least 60 percent alcohol, advises the Centers for Disease Control and Prevention (CDC). (4)

Another important way to prevent diarrhea in children is to get them vaccinated against rotavirus, which causes severe diarrhea mostly in babies and young kids. The virus can also lead to vomiting, fever, and dehydration. The CDC recommends that babies get their first dose of the orally administered (taken by mouth) rotavirus vaccine before they’re 15 weeks old. The second dose — and third dose, depending on the brand of vaccine — should be taken before babies are 8 months old.

The rotavirus vaccine will protect almost all babies from severe diarrhea caused by rotavirus, and most babies who are vaccinated will not get rotavirus diarrhea at all, the CDC says. (5)

Finally, you can avoid traveler's diarrhea by watching what you eat and drink while traveling abroad — especially in developing countries — and by talking to your doctor before you leave about taking antibiotics as a precaution, notes the CDC. (6)

Learn More About How to Prevent Diarrhea

Sometimes, diarrhea may signal a health problem that requires medical attention.

But in most cases, a bout of diarrhea will clear up in a few days and not lead to any further health problems. There are steps you can take at home to help treat diarrhea so that it goes away faster.

If you have diarrhea, the following may help you feel better.

Replace fluids. In addition to getting enough water, it’s important to replenish lost electrolytes (minerals like sodium and potassium) by consuming water with added electolytes, sports drinks, or fruit juice and broth. Pay attention to the amount of sugar in these drinks, because too much sugar can worsen diarrhea symptoms.

Eat a bland diet. A bland diet may be easier on your digestive system and help reduce diarrhea symptoms, according to the National Library of Medicine. A bland diet consists of foods that are soft, not spicy, and low in fiber. You should also avoid raw foods, fried foods, and drinks with alcohol or caffeine in them.

Try over-the-counter (OTC) medications. Over-the-counter medication can help ease the discomfort that comes with diarrhea. Options include loperamide, commonly known as Imodium, and bismuth subsalicylate, or Pepto-Bismol. But ask your doctor before taking these drugs, since they may not be right for all cases of diarrhea.

Antibiotics may be needed. If your diarrhea is caused by a bacterial infection, your doctor will prescribe antibiotics to help you get better. Antibiotics can also treat diarrhea caused by parasites. If your diarrhea is caused by a virus, though, antibiotics will not help.

Treat underlying problems. Diarrhea may be a symptom of a more serious health condition, such as a food allergy or digestive disorder, or even a systemic illness. Your doctor will work with you to figure out the underlying issue through testing and come up with an appropriate treatment plan. (2)

Learn More About Treatment for Diarrhea

When diarrhea strikes, it can cause your body to lose more fluid than it takes in, leading to dehydration. Dehydration can be especially dangerous for children, older adults, and people with a weakened immune system, according to the Mayo Clinic.

Severe dehydration may be life-threatening if it isn’t recognized and treated. While it’s best to prevent dehydration in the first place by taking in enough fluids and electrolytes when you have diarrhea, you should also look out for symptoms of dehydration.

In adults, dehydration may cause thirst, dry mouth, reduced urination, dark urine, weakness, light-headedness, or fatigue. In babies and young children, you should also look out for a fever above 102 degrees F, crying without tears, dry diapers, reduced responsiveness, or a sunken appearance in your child’s face or abdomen.

You should see a doctor right away if you experience black and tarry stools, stools that contain blood or pus, or symptoms of dehydration combined with six or more loose stools and or vomiting, according to the NIDDK.

Learn More About Dehydration and How to Avoid It When You Have Diarrhea

According to a review published in the New England Journal of Medicine, it’s estimated that there are 179 million cases of acute diarrhea each year in the United States. (7)

A paper published in 2017 in the journal Clinical Gastroenterology and Hepatology states that chronic diarrhea affects as many as 5 percent of the population at any given time. (8)

In less-developed countries, diarrhea is a much more severe problem. Worldwide, diarrhea kills about 525,000 children under age 5 each year, according to the World Health Organization, and it’s also the leading cause of malnutrition in young children. The organization notes that many cases of diarrhea could be prevented through access to safe drinking water and basic sanitation.

Diarrhea and other gastrointestinal symptoms can be a sign of a disorder of the digestive system, such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD) like Crohn’s disease or ulcerative colitis.

Diarrhea may also be related to celiac disease, lactose intolerance, or food allergies. If your diarrhea becomes chronic, a doctor can help determine if one of these conditions is the cause, the Mayo Clinic notes. (9)

Diet and Diarrhea

Certain foods can worsen diarrhea symptoms, so it’s good to know which foods are probably safe to eat and which ones you should avoid.

Stick to plain, simple foods — such as oatmeal, bananas, plain rice, and applesauce — especially in the first 24 hours after you develop diarrhea.

Other bland foods that are easy on the stomach include bread and toast, boiled potatoes, plain crackers, and hot cereals.

Foods that may aggravate diarrhea and should be avoided include fatty or fried foods, milk, butter, ice cream, cheese, alcoholic or carbonated beverages, foods or beverages containing artificial sweeteners, and foods that may be spoiled, according to the National Library of Medicine. (10)

Learn More About Diet and Diarrhea

Diarrhea and Your Period

Many women experience diarrhea and changes in their bowel habits during their menstrual period. The exact reason why this happens is not fully understood, but doctors believe the root cause is prostaglandins, the chemicals released during your period that allow your uterus and your intestines to contract.

Women who often experience bouts of diarrhea during their period can prepare ahead of time by having easy access to over-the-counter medication like Imodium (loperamide) and staying well hydrated by drinking plenty of fluids. (11)

Learn More About Diarrhea and Your Period

Traveler’s Diarrhea

Depending on the destination and season of travel, 30 to 70 percent of travelers will be affected by traveler's diarrhea, according to the CDC.

There are a number of steps people can take to avoid traveler's diarrhea.

Check the CDC’s website for travel warnings. The travelers’ health website maintained by the CDC will alert you to disease warnings and health risks for various countries.

Watch what you eat and drink. In certain countries, the CDC will advise taking steps to avoid ingesting parasites that can make you sick, such as avoiding raw fruits and vegetables unless you peel them yourself, avoiding raw or undercooked meat or seafood, and sticking to hot, well-cooked foods. In certain countries, tap water is not safe to drink. In such places, you should drink bottled water and avoid tap water and ice cubes.

Talk to your doctor about antibiotics. Before you take off for your destination, make an appointment with your healthcare provider to discuss possible health risks while on your trip. If you are going to a developing country for an extended period of time, ask your doctor about antibiotics. (6)

Learn More About Traveler's Diarrhea

Diarrhea is known to occur in some people who develop COVID-19. A study published in March 2020 in the American Journal of Gastroenterology found that diarrhea was often a symptom in people with less-severe disease. Of the 206 patients included in the study, 48 people had only digestive symptoms, while 69 had both digestive and respiratory symptoms. Between both groups, 67 people had diarrhea, 19 percent of whom experienced diarrhea as their first symptom. (12)

More recently, diarrhea has emerged as a common symptom in post-COVID syndrome, also known as long COVID. A study published in November 2021 found that diarrhea was reported in 46 percent of a group of participants with long COVID, who had developed COVID-19 a median of 219 days earlier. For comparison, 40 percent of this study group reported having diarrhea during the initial acute phase of COVID-19.

Favorite Organizations for Information on Diarrhea

National Institute of Diabetes and Digestive and Kidney Diseases

Brought to you by an institute within the U.S. National Institutes of Health, this website offers information on symptoms, diagnosis, and treatment. You can learn about chronic diarrhea and find out how to participate in clinical trials.

American College of Gastroenterology (ACG)

The ACG is a professional organization dedicated to the prevention, diagnosis, and treatment of digestive disorders. You can learn all about acute and chronic diarrhea on this website and find a gastroenterologist in your area.

National Cancer Institute

Cancer and some of the treatments for it can cause diarrhea. The National Cancer Institute website offers tips on how to manage it. You can also download audio on the topic.

Centers for Disease Control and Prevention (CDC)

According to the CDC, 30 to 70 percent of travelers experience diarrhea every year, depending on where they go. Find out how to prevent and treat the condition.

Favorite Support Groups for People Dealing With Diarrhea

IBS Network

While diarrhea usually lasts a day or two, chronic diarrhea can indicate a gastrointestinal condition like irritable bowel syndrome. The IBS Network can link you to groups in your community, so you can meet others for support and tips on dealing with the condition.

Irritable Bowel Syndrome and Digestive Health Support Forum

This patient-led education organization provides information on gastrointestinal disorders like IBS diarrhea and IBD. The forum has discussions on the gut microbiome and the tried-and-tested remedies of diarrhea sufferers.

Favorite Websites With Information on Remedies for Diarrhea

FamilyDoctor.org

This website, by the American Academy of Family Physicians, offers information on over-the-counter remedies for diarrhea. It lists potential side effects of common OTC medications and gives information on potential side effects with other medications.

The Oregon Clinic

When you’re dealing with diarrhea, it’s good to eat foods that can help solidify your stools. The BRAT diet (bananas, rice, apples, and toast) can help with that. This page on the Oregon Clinic’s website provides a sample BRAT diet plan and information on what to do if diarrhea doesn’t go away in 24 hours.