What Is Diarrhea?

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Diarrhea is a very common condition that affects the digestive tract. It is characterized by loose or watery stools occurring at least three times per day.

In the United States, diarrhea affects adults about once per year and young children twice per year. It is more common in people who live in or travel to developing countries. It usually resolves on its own after one or two days. When diarrhea lasts more than a few days, it may be a sign of a serious health problem. 

This article discusses the symptoms, causes, and treatment options for diarrhea.

A person flushing a toilet

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Acute vs. Severe Diarrhea

Most cases of diarrhea are considered acute and do not last long. Diarrhea usually goes away on its own after a few days. The cause is often unknown.

Severe cases of diarrhea last longer than four days and require treatment. Severe diarrhea can last weeks and may require intravenous fluids to prevent dehydration.

What Causes Diarrhea?

There are several possible causes of diarrhea, and they range from mild to serious. 

Acute Diarrhea Causes

The most common causes of acute diarrhea are infection, traveler’s diarrhea, and medication side effects. 

Infections that lead to diarrhea include:

Traveler’s diarrhea usually spreads through contaminated food and water, where bacteria and parasites can live. When ingested, the bacterium or parasite settles into the digestive tract and causes illnesses. While most cases of traveler’s diarrhea are acute, some parasites can cause chronic problems. 

Medications that have been linked with acute diarrhea include:

  • Antibiotics
  • Antacids 
  • Magnesium
  • Chemotherapy and other cancer treatments 

Chronic Diarrhea Causes

Chronic diarrhea lasts for weeks or longer. Certain infections, food allergies or intolerances, digestive tract problems, surgery complications, or long-term medication use may cause it. 

Causes of chronic diarrhea include:

  • Infections: Certain infections cause diarrhea that does not resolve quickly. After the infection, some people may have trouble digesting lactose (found in dairy). This leads to chronic diarrhea.
  • Food allergies: Allergies to cow’s milk, soy, cereal grains, eggs, or seafood can cause diarrhea anytime those foods are ingested. 
  • Food intolerances: Lactose intolerance is a common cause of diarrhea after eating dairy; other food intolerances that can lead to diarrhea include fructose and sugar-alcohol intolerances. 
  • Digestive tract problems: Chronic digestive disorders, including celiac disease, Crohn’s disease, irritable bowel syndrome (IBS), and ulcerative colitis, cause bouts of diarrhea. 
  • Abdominal surgery: Surgery of the appendix, gallbladder, large intestine, liver, pancreas, small intestine, spleen, or stomach can lead to long-term diarrhea.
  • Long-term medications: Antibiotics change the balance of normal gut flora, so taking them long-term can increase the risk of certain infections like Clostridioides difficile (C. diff).

Symptoms of Diarrhea

Diarrhea is a condition that causes loose, watery stools, abdominal cramping and pain, and an urgent need to use the bathroom.

If an infection causes diarrhea, additional symptoms may include: 

If a malabsorption disorder causes diarrhea, the symptoms can include:

  • Bloating 
  • Gas 
  • Changes in appetite
  • Weight loss
  • Greasy, foul-smelling stools 

See a healthcare provider immediately if you notice black stool when you have diarrhea. This could mean that there is bleeding in your digestive tract.

Diarrhea and Dehydration

Diarrhea for a few days can lead to dehydration, when your body loses more fluid than it takes in. Symptoms of dehydration may include:

Symptoms of dehydration in babies and young children include: 

  • No wet diapers for three or more hours
  • No tears when crying 
  • Sunken soft spot on the head 

Diagnosing Diarrhea

Most cases of diarrhea last for a couple of days. However, when it does not improve on its own, it's important to see a healthcare provider to determine the cause and if you're dehydrated. They will ask questions about when diarrhea started and if the symptoms worsened, and recent changes in your diet or medications.

Other diagnostic tools may include:

  • Stool study: Stool is sent to a lab to check for abnormal bacteria in the digestive tract.
  • Sigmoidoscopy: A short, flexible tube with a light is advanced through the rectum into the last third of the large intestine to inspect the digestive tract and take biopsies if needed.
  • Colonoscopy: A tube is inserted into the entire length of the large intestine to look for abnormal growths or any red, swollen, or bleeding tissue.
  • Imaging: Computed tomography (CT) scan and magnetic resonance imaging (MRI) may be used to detect structural abnormalities.
  • Fasting tests: These tests detect if you cannot digest certain foods or have intolerances.
  • Blood tests: They are used to diagnose thyroid disease, anemia, low levels of specific vitamins, or celiac disease.

How to Stop Diarrhea

Most cases of diarrhea resolve on their own without treatment. If you have had diarrhea for over two to three days, you may need treatment to prevent dehydration. The treatment plan depends on the type of diarrhea, its underlying causes, how severe it is, and your overall health. 

Over-the-Counter (OTC) Treatment

To treat diarrhea at home, start hydrating yourself as much as possible. OTC antimotility agents like Immodium (loperamide) can slow down your gastrointestinal tract and decrease the amount and frequency of diarrhea. 

Prescription Medication

Prescription medication may be needed for severe diarrhea. If a healthcare provider is concerned that you are dehydrated, they may recommend intravenous (IV) fluids. Antibiotics may be prescribed if a bacterial infection causes diarrhea. Parasitic infections are treated with antiparasitic medication. 


Replacing the fluids lost during diarrhea is an important part of treatment. Start by drinking more fluids and eating soft, bland foods. Adults can rehydrate with the following types of drinks:

  • Water
  • Fruit juice
  • Sports drinks
  • Salty broth 

Healthcare providers recommend that children drink oral rehydration solutions such as Pedialyte to replace lost fluids. 

Treatment for Babies and Young Children

Dehydration is a serious health problem for babies and young children. Treating diarrhea and watching for any signs of dehydration in this age group is critical. To prevent dehydration in babies and young children, offer small, frequent doses of an oral rehydration solution. For babies who are nursing, offer breastfeeding often. 

Babies and children should avoid sports drinks and fruit juices because they are very sugary and may upset their stomachs. They should not take antidiarrheal medications unless recommended by a healthcare provider. 

Can You Prevent Diarrhea?

Diarrhea is very common and cannot always be prevented. However, there are ways to lower your risk. Use the following strategies:

  • Wash your hands frequently. 
  • Use hand sanitizer. 
  • Clean and cook your food safely.
  • Stay up to date on vaccines such as rotavirus
  • Clean door knobs and frequently-touched surfaces with a cleaner that kills viruses.

People who travel to developing countries are at an increased risk of traveler’s diarrhea. To lower your risk while traveling, keep the following tips in mind:

  • Avoid tap water (even when brushing your teeth).
  • Do not use ice.
  • Avoid milk and milk products that are not pasteurized.
  • Do not eat raw fruits or vegetables.
  • Ask for all meat and fish to be cooked well-done.
  • Only eat meat and shellfish that are hot when served.
  • Avoid any food from street vendors or food trucks.

When to Seek Medical Care for Severe Diarrhea

Most cases of diarrhea can be safely treated at home. If you have a compromised immune system or are an older adult, call a healthcare provider whenever you experience diarrhea. It is also important to contact a provider if you develop symptoms of dehydration or fever, vomiting, or six or more stools in 24 hours.

Seek medical care if you develop any of the following symptoms with diarrhea:

  • Severe pain in the abdomen or rectum
  • Diarrhea that is worsening 
  • Blood in the stool
  • Black, tarry stools
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. MedlinePlus. Diarrhea.

  2. Johns Hopkins Medicine. Diarrhea.

  3. Centers for Disease Control and Prevention. Management of acute diarrhea.

  4. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of diarrhea.

  5. American College of Gastroenterology. Diarrheal diseases - acute and chronic.

  6. Nemours KidsHealth. Diarrhea.

By Carrie Madormo, RN, MPH
Carrie Madormo, RN, MPH, is a health writer with over a decade of experience working as a registered nurse. She has practiced in a variety of settings including pediatrics, oncology, chronic pain, and public health.