Diarrhea

Medically Reviewed by Carmelita Swiner, MD on January 04, 2023
4 min read

When you have diarrhea, your bowel movements (or stools) are loose and watery. It’s common and usually not serious.

Many people get diarrhea a few times a year. It normally lasts 2 to 3 days. Some people get it more often. That could be because they have irritable bowel syndrome (IBS) or other conditions.

Usually, diarrhea happens because of a virus that gets into your gut. Some people call it "intestinal flu" or "stomach flu."

Other causes include:

  • Allergies to certain foods
  • Diseases of the intestines (such as Crohn's disease or ulcerative colitis)
  • Eating foods that upset the digestive system
  • Infection by bacteria (the cause of most types of food poisoning) or other organisms
  • Laxative abuse
  • Running (Some people get “runner’s diarrhea” for reasons that aren’t clear.)
  • Some cancers
  • Surgery on your digestive system
  • Trouble absorbing certain nutrients, also called “malabsorption”

Diarrhea may also follow constipation, especially for people who have irritable bowel syndrome (IBS).

You may have:

  • Bloating in your belly
  • Thin or loose stools
  • Watery stools
  • An urgent feeling that you need to have a bowel movement
  • Nausea and throwing up

Most cases of diarrhea are nothing more than a brief inconvenience. But sometimes, they warn of a serious condition. Talk with your doctor if your child has diarrhea for more than 24 hours. If you have it for more than 3 days, make an appointment.

Also, be sure to let your doctor know about your diarrhea if you have cancer, or have had recent treatment for it.

More serious symptoms of diarrhea include:

  • Blood or mucus in your stool
  • Weight loss

If you have watery stools more than three times a day and you're not drinking enough fluids, you could become dehydrated. That can be a serious problem if it's not treated.

Call your doctor right away if you have:

  • Blood in your diarrhea or black, tarry stools
  • A fever that is high (above 101 F) or that lasts more than 24 hours
  • Diarrhea lasting longer than 2 days
  • Nausea or throwing up that prevents you from drinking liquids to replace lost fluids
  • Severe pain in your belly (especially the right lower quadrant) or rear end
  • Diarrhea after coming back from a foreign country

These can be warning signs of things like:

Also, call your doctor right away if you have diarrhea and any of these signs of dehydration:

  • Dark urine
  • Smaller than usual amounts of urine or, in a child, fewer wet diapers than usual
  • Rapid heart rate
  • Headaches
  • Dry skin
  • Crankiness
  • Confusion

Your doctor will ask about your medical history and what medications you take, as well as what you’ve eaten or had to drink recently. They will give you a physical exam to look for signs of dehydration or belly pain.

Certain tests can help pinpoint the cause of your diarrhea, including:

  • Blood tests to look for certain diseases or disorders
  • Colonoscopy, in rare cases, in which your doctor looks inside your colon with a thin, flexible tube that holds a tiny camera and light. They can also use this device to take a small sample of tissue. Or your doctor might need to do only a sigmoidoscopy, which looks at just the lower colon.
  • Stool tests to look for bacteria or parasites

If your case is mild, you may not need to take anything. Adults can take an over-the-counter medicine such as bismuth subsalicylate or loperamide, which you can get as liquids or tablets.

You also need to stay hydrated. You should drink at least six 8-ounce glasses of fluids each day. Choose electrolyte replacement drinks or soda without caffeine. Chicken broth (without the fat), tea with honey, and sports drinks are also good choices. Instead of drinking liquids with your meals, drink liquids between meals. Sip small amounts of fluids often. Liquid probiotics may also help.

Your rectal area may become sore because of all the bowel movements that diarrhea brings. You may have itching, burning, or pain when you go to the bathroom.

For relief, take a warm bath or sitz bath. Afterward, pat the area dry (don’t rub) with a clean, soft towel. You may also try using a hemorrhoid cream or petroleum jelly on the affected area. If this continues for several days, you should contact your doctor.

If you still have diarrhea after 4 weeks, then you have chronic diarrhea.

To figure out the cause, your doctor will want to know your symptoms and medical history. You'll get the most out of your appointment if you can tell them:

  • How long you've had diarrhea
  • Whether your diarrhea comes and goes, or is continuous
  • If you think certain foods and situations make things better or worse
  • If your stool looks bloody, oily, fatty, or watery
  • Other symptoms you have and how long you’ve had them
  • If you have a family history of chronic diarrhea
  • Places you've traveled to recently
  • Unusual foods you've tried in the last little while
  • Any medication or supplements you're taking
  • If you've lost a lot of weight