[Skip to Content]

Diarrhea

Reviewed by: Kate M. Cronan, MD

What Is Diarrhea?

Diarrhea is frequent, soft or loose bowel movements (poop). Most people get diarrhea from time to time. It usually doesn't last long and often gets better on its own.

What Causes Diarrhea?

Diarrhea is usually caused by an infection in the intestines. The germs that cause the infection are:

  • viruses (most common)
  • bacteria
  • parasites

Viruses

Viral gastroenteritis (the "stomach flu") is a common illness. It causes diarrhea and, often, nausea and vomiting. The symptoms usually last a few days. The viruses that cause viral gastroenteritis can pass through a household (or a college dorm or other place where lots of people live together) quickly because they're highly infectious.

Luckily, the diarrhea usually goes away on its own in a few days. For healthy teens and adults, viral gastroenteritis is a common but minor inconvenience. But for little kids and people with chronic illnesses, it can lead to dehydration that needs medical attention.

Bacteria

In developed countries like the United States, outbreaks of diarrhea are most often due to what we call food poisoning. Food poisoning happens when toxins are made by bacteria in food that isn't handled, stored, or cooked safely.

Other bacterial infections that can cause diarrhea include E. coli, salmonellosis, and shigellosis.

Parasites

The Giardia parasite spreads easily through contaminated water and human contact. This parasite can spread in water parks and pools because it is resistant to chlorine treatment. Bathing in and drinking water from contaminated streams or lakes can lead to an infection and chronic diarrhea. Infants in childcare settings can become infected with Giardia and bring the parasite home, causing diarrhea in family members.

Another parasite, Cryptosporidium, is a common culprit behind diarrhea epidemics in childcare centers and other public places. Cryptosporidium often causes watery diarrhea that can last for 2 weeks or more.

What Else Can Cause Diarrhea?

Sometimes, people get diarrhea from:

What Are the Signs & Symptoms of Diarrhea?

People often get crampy belly pain first, followed by diarrhea that can last 3–5 days. Other symptoms may include:

  • fever
  • loss of appetite
  • nausea (uncomfortable feeling before vomiting)
  • vomiting
  • weight loss
  • dehydration

How Is Diarrhea Treated?

Most infections that cause diarrhea, especially viral infections, will go away without treatment. Taking it easy at home and drinking plenty of fluids to avoid dehydration are the best ways to ride out the illness. If you do become dehydrated, you might need to go to the hospital for intravenous (IV) fluids to replace those lost to diarrhea, vomiting, and fever.

If you go to your doctor, you may give a stool sample so he or she can find out what type of infection you have. Whether you need medicine will depend on which germ is causing the illness. A parasitic infection will be treated with anti-parasitic medicine. Sometimes, diarrhea caused by bacteria is treated with antibiotics to prevent the infection from spreading throughout the body.

How Can Diarrhea Be Prevented?

It's almost impossible to prevent all cases diarrhea. But there are some ways to make it less likely:

  • Wash your hands well and often, especially after using the toilet and before eating. Hand washing is the best way to prevent diarrheal infections that pass from person to person.
  • Keep bathroom surfaces like sinks and toilets clean.
  • Wash fruits and vegetables well before eating.
  • Clean kitchen counters and cooking utensils well after they've been in contact with raw meat, especially poultry.
  • Refrigerate meats as soon as possible after bringing them home from the store. Cook them until they're no longer pink. Refrigerate all leftovers as soon as possible.
  • Never drink from streams, springs, or lakes unless local health authorities have checked that the water is safe for drinking.
  • Avoid washing pet cages or bowls in the same sink that you use to prepare food. And try to keep pet feeding areas separate from family eating areas.

When Should I Call My Doctor?

Tell an adult if you have diarrhea, fever, vomiting, or severe belly pain. That person can help you decide whether to call your doctor.

If you feel listless and your mouth and skin feel dry, or if your bowel movements contain blood or mucus, you should contact or see a doctor right away. Also go to the doctor if you are vomiting so much that you can't keep down fluids or if your symptoms last more than 3 days.

What Can I Do to Feel Better?

You'll feel better if you stay well hydrated, so drink lots of water. Electrolytes (sodium and potassium) are also lost and need to be replaced because the body cannot function properly without them. Try sipping broth or soup, which contain sodium, and diluted fruit juice (with no added sugar), which contains potassium.

When you feel ready to eat something more substantial, try soft fruits or vegetables, which also contain potassium. Avoid milk products and fatty, high-fiber, or very sweet foods until the diarrhea eases. And don't drink sports drinks or soft drinks — they contain electrolytes, but their high sugar content can make diarrhea worse.

As uncomfortable as diarrhea may be, it is usually short-lived. Drink enough fluids and follow your doctor's instructions, and you feel better in no time.

Reviewed by: Kate M. Cronan, MD
Date reviewed: January 2019