Author: Marisa Healy, BSN, RN
Last Reviewed: February 05, 2024

Diarrhea is when you pass three or more loose or watery stools in a day.  Diarrhea may or may not cause pain or discomfort in your abdomen (belly) and/or rectum. Diarrhea should never be ignored, especially if you have cancer. Diarrhea can cause:

  • Dehydration (not enough fluid in your body).
  • Loss of needed nutrients in your body.
  • Weight loss.
  • Fatigue.

You should always tell your provider if you are having diarrhea.

What causes diarrhea?

There are many things that can cause diarrhea:

  • Diseases of the bowel.
  • Some treatments, such as medications, radiation therapy, and surgery that affects your bowel.
  • Bowel infections.
  • Anxiety.
  • Some foods and nutritional supplements.

What can I do to prevent or lessen diarrhea?

You can change your diet to help manage diarrhea. Ways to decrease diarrhea are to:

  • Eat bland and easy-to-digest foods like chicken, fish, eggs, pudding, mashed potatoes, noodles, rice, yogurt, cottage cheese, cream of wheat, farina, smooth peanut butter, white bread, bananas, applesauce, canned fruit, and well-cooked vegetables.
  • Stay away from dried fruits, cruciferous vegetables (broccoli, bok choy, kale, cauliflower, cabbage, peas), raw vegetables, whole grains, beans, and legumes.
  • Find ways to get more soluble fiber in your diet. Soluble fiber is a type of fiber found in some foods. This kind of fiber absorbs fluid and can help relieve diarrhea. Foods high in soluble fiber are:
    • Fruits: Applesauce, bananas (ripe), canned fruit, orange, and grapefruit.
    • Vegetables: Boiled potatoes.
    • Breads & pastas: White rice and products made with white flour.
    • Cereals: Oatmeal, cream of rice, cream of wheat and farina.
  • Eat small amounts of food 5-6 times a day, instead of three large meals.
  • Add nutmeg to foods to slow down the movement of food through the intestines.
  • Drink 6-8 glasses of non-caffeine drinks per day. Water is always a good choice. Some sports drinks or broth can help replace minerals and electrolytes lost through diarrhea.
  • Clear liquids may be easier for you to drink. Try clear fruit juices like apple or cranberry, ginger ale, and gelatin.
  • Avoid caffeine (cola, coffee, tea), alcohol, milk or milk products, chocolate, dried fruits, beans, or popcorn. Try to stay away from fatty, fried, greasy, or spicy foods.
  • Avoid very hot and cold beverages.

Keep a food diary to help figure out which foods make diarrhea better or worse for you.

Rectal Care

You may have pain or irritation of your rectum if you have diarrhea. There are some things you can do to safely ease this discomfort:

  • Clean the outside rectal area well after each bowel movement. Use warm water and soap, and pat dry with a soft towel. This will help prevent burning and irritation.
  • Check your rectal area each day for red, scaly, or broken skin. Report this to your care team.
  • Soak in a warm bath or use a sitz bath, which gives a continuous, gentle flow of warm water over the rectal area while sitting on the toilet. Sitz baths can be bought at your local drug store.
  • Barrier creams can help protect the skin. Ask your provider about a numbing ointment if the area becomes very sore.

Can I take over-the-counter medications?

You should not take any over-the-counter medications without talking to your provider first. This includes all over-the-counter anti-diarrheal medications, such as Kaopectate®, Immodium AD®, and Pepto-Bismol®.

Diarrhea can be caused by an infection or a medication you are receiving. Your stool will need to be tested before you take any medication to stop the diarrhea. If your provider decides that it is okay to take these medications, they may tell you to take a different dose than the package directions.

When should I call my provider?

Diarrhea can cause dehydration and can be uncomfortable. Call your provider right away if you:

  • Are having 6 or more loose bowel movements each day for more than 2 days in a row.
  • See blood in or around the anal area, in the stool, on the toilet paper, or in the toilet bowl.
  • Are peeing less than normal.
  • Are unable to drink fluids for more than 24 hours.
  • Have a fever over 100.4°F (38°C).
  • Have weight loss of 5 pounds or more since the diarrhea started.
  • Have a swollen and/or painful abdomen.

If you have changes to your bowel habits, such as diarrhea, tell your care provider. They will help you manage the diarrhea as safely as possible. Be sure to talk with your provider before taking any medications for diarrhea.

American Cancer Society. Diarrhea. 2020. Taken from https://www.cancer.org/cancer/managing-cancer/side-effects/stool-or-urine-changes/diarrhea.html 

Medline Plus. Diarrhea. 2021.

National Cancer Institute. Diarrhea and Cancer Treatment. 2021.

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