Diarrhea is the passage of loose or watery stools 3 or more times a day with or without discomfort. It happens when water in the intestine isn’t being absorbed back into the body for some reason.

Sometimes, diarrhea can be caused by an overflow of intestinal liquids around stool (poop) that’s partly blocking the intestine. This is called impaction. Other causes can include chemotherapyradiation therapy to the belly; medicines; infectionssurgery; liquid food supplements that are too concentrated with vitamins, minerals, sugar, and electrolytes; and tumor growth. Diarrhea caused by chemotherapy or radiation therapy may last for up to 3 weeks after treatment ends.

Avoid high-fiber foods, which might make diarrhea worse. These include nuts, seeds, whole grains, legumes (beans and peas), dried fruits, and raw fruits and vegetables. You should avoid high-fat foods, like fried and greasy foods, too, because they also can make diarrhea worse.

After stomach or bowel surgery, some people may be sensitive to very sweet or high-carbohydrate foods as well. Stay away from gassy foods and carbonated drinks, too. Be sure to sip fluids during the day to prevent dehydration. Once the diarrhea has stopped, slowly start eating foods with fiber.

What the patient can do

  • Try a clear liquid diet (one that includes water, weak tea, apple juice, peach or apricot nectar, clear broth, Popsicles, and gelatin with no solids added) as soon as diarrhea starts or when you feel that it’s going to start. Avoid acidic drinks, such as tomato juice, citrus juices, and fizzy soft drinks.
  • Room temperature drinks might be better tolerated than cold or hot drinks. Try to keep them caffeine-free.
  • Avoid milk or milk products if they seem to make diarrhea worse. Yogurt and buttermilk are ok.
  • Allow carbonated drinks to become slightly “flat” before drinking by pouring them into a glass and letting them sit at least 10 minutes.
  • Drink and eat high-sodium (salt) foods like broths, soups, sports drinks, crackers, and pretzels.
  • Drink at least 1 cup of liquid after each loose bowel movement. Try water, sports drinks, or bouillon.
  • Do not chew sugar-free gum or eat candies and desserts made with sugar alcohol (i.e., sorbitol, mannitol, or xylitol).
  • Eat small meals often. Don’t eat very hot or spicy foods.
  • Avoid greasy foods, bran, raw fruits and vegetables, and caffeine.
  • Avoid pastries, candies, rich desserts, jellies, preserves, and nuts.
  • Don’t drink alcohol or use tobacco.
  • Be sure your diet includes foods that are high in potassium (such as bananas, potatoes, apricots, and sports drinks like Gatorade® or Powerade®). Potassium is an important mineral that you may lose if you have diarrhea.
  • Keep track of the amount and frequency of bowel movements.
  • Clean your anal area with a mild soap after each bowel movement, rinse well with warm water, and pat dry. Or use baby wipes to clean yourself.
  • Apply a water-repellent ointment, such as A&D Ointment® or petroleum jelly, to the anal area.
  • Sitting in a tub of warm water or a sitz bath may help reduce anal discomfort.
  • Take medicine for diarrhea as prescribed.
  • When the diarrhea starts to improve, try eating small amounts of foods that are easy to digest such as rice, bananas, applesauce, yogurt, mashed potatoes, low-fat cottage cheese, and dry toast. If the diarrhea keeps getting better after a day or 2, start small regular meals.

What caregivers can do

  • See that the patient drinks about 3 quarts of fluids each day.
  • Keep a record of bowel movements to help decide when the cancer team should be called.
  • Ask before using any over-the-counter diarrhea medicine.
  • Check the anal area for red, scaly, broken skin.
  • Protect the bed and chairs from being soiled by putting pads with plastic backing under the patient.

Call the cancer team if the patient:

  • Has 6 or more loose bowel movements a day with no improvement in 2 days
  • Has blood in the stool or around anal area
  • Loses 5 pounds or more after the diarrhea starts
  • Has new belly pain or cramps for 2 days or more
  • Does not urinate (pee) for 12 hours or more
  • Does not drink liquids for 24 hours or more
  • Has a fever of 100.5° F or higher when taken by mouth
  • Gets a puffy or swollen belly
  • Has been constipated for several days and then begins to have small amounts of diarrhea or oozing of liquid stool, which could suggest an impaction (severe constipation)


The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

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Last Medical Review: June 8, 2015 Last Revised: July 29, 2019

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