Diarrhea

Medically Reviewed by Poonam Sachdev on April 30, 2024
Written by Alyson Powell Key
6 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.

There are different types of diarrhea, including:

Acute diarrhea

This most common type lasts a couple of days at the most and usually gets better without treatment.

Persistent diarrhea

This kind lasts for a couple of weeks up to a month.

Chronic diarrhea

This type of diarrhea lasts longer than a month or appears and disappears over time. It could be a sign of a serious health condition that needs your doctor's attention.

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 like parasites
  • Laxative abuse or a reaction to medications like antibiotics and certain cancer drugs
  • 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”
  • Overactive thyroid (hyperthyroidism)

Diarrhea may also follow constipation, especially for people who have 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
  • Leaking stool, and you can't control your bowels (incontinence)

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
  • A rapid heart rate
  • Headaches
  • Dry skin
  • Crankiness
  • Confusion

Your doctor will ask about your medical history, what medications you take, and 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 specific diseases or disorders
  • A 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
  • An endoscopy to check your stomach and intestines to make sure there aren't any growths or problems like ulcers that could be causing your diarrhea
  • Imaging tests that can show if there's anything wrong with how your organs are shaped or formed
  • Fasting tests, which can reveal if you have trouble digesting specific foods (food intolerance) or if certain foods trigger an immune response (food allergy)
  • A hydrogen breath test, which can find out if you're intolerant to lactose or fructose and if you have too much bacteria in your gut

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, available as liquids or tablets. Your doctor could also suggest: 

  • Antibiotics or anti-parasitic drugs get rid of germs that cause infection
  • Medicine to treat a health condition that causes diarrhea, such as inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS)
  • A probiotic, which fights diarrhea by introducing good bacteria to your gut 

Home remedies and lifestyle changes can also help you to get rid of diarrhea.

Drink plenty of fluid

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.

BRAT diet

BRAT is an acronym for bananas, rice (white rice), applesauce, and toast. Eating these foods will help firm your stools. In addition to this diet, you can also try potatoes, noodles, lean beef, fish, and skinless chicken or turkey. 

Avoid caffeine and alcohol

Caffeine, which is found in coffee, soda, certain teas, and chocolate, can make diarrhea worse. Alcohol can make you dehydrated.

Avoid gas-causing foods

This includes beans, cabbage, Brussels sprouts, beer, and fizzy drinks. It's also best to avoid dairy while you have diarrhea since the condition can briefly make you lactose intolerant.

Your rectal area may become sore from all the bowel movements that diarrhea brings. You may have itching (also called pruritus ani), 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

There are steps you can take to lower your chances of getting diarrhea from infections or contaminated food:

  • Wash your hands thoroughly after using the bathroom or handling food. Hand sanitizer is an alternative.
  • Get the rotavirus and COVID-19 vaccines to lower your odds of getting sick from these illnesses, which may trigger diarrhea.
  • Keep food at safe temperatures and fully cook it.
  • Avoid untreated water, ice cubes, and unpasteurized drinks while traveling.
  • Avoid raw or undercooked meats, shellfish, and unwashed fruits and vegetables while traveling.

Common causes of diarrhea include infections, food allergies, and food poisoning. It's often due to a virus infecting your gut, but it can also result from medications or dietary issues. Diarrhea causes loose or watery stool and can last from a day to several weeks. Treatment usually involves managing symptoms at home with plenty of fluids and changes to your diet. You can help avoid diarrhea by practicing good hygiene, getting vaccinated, storing food properly, and being cautious with food and drink, especially while traveling.