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Learn about diarrhea in people with cancer in this guide from The ONE Group (Oncology – Nutrition – Exercise) at Penn State College of Medicine.

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What you should know

Diarrhea and cancer

Diarrhea is experiencing soft, loose and watery bowel movements.

Foods and liquids pass through the bowel so quickly that your body cannot absorb enough nutrition, vitamins and minerals from them.

It is a common side effect that can be caused by cancer treatment, including chemotherapy and other medications, radiation therapy to the abdomen and surgery.

Other potential causes include infection, food sensitivity and emotional upset.

BRAT diet

The term “BRAT” stands for bananas, rice, applesauce and toast.

This diet is often recommended to those experiencing diarrhea because these foods are gentle on the stomach and the low fiber content can help by firming stool.

What you can do: Improving your eating behavior

Eat BRAT diet foods

In addition to bananas, rice, applesauce and toast, other foods that fall into the BRAT diet are:

  • Soups: clear broth, such as chicken, vegetable or beef
  • Liquids: cranberry, apple and grape juice, tea (without caffeine), water
  • Snacks: canned peaches, pears, sweet potatoes, crackers, cream of wheat, eggs, gelatin, oatmeal, creamy peanut butter

Tips to improve your eating behavior when you’re experiencing diarrhea

  • Drink at least one cup of liquid after each loose bowel movement. Try water, sports drinks or bouillon.
  • Avoid high-fiber foods, such as nuts, whole grains, legumes, fruits and vegetables.
  • Drink liquids at room temperature. This may be easier to take than very hot or cold drinks.
  • Eat small, frequent meals and snacks.
  • Avoid greasy, fried, spicy or very sweet foods.
  • Limit milk or milk products to two cups a day.
  • Drink and eat high-sodium (salt) foods like broths, soups, sports drinks, crackers and pretzels.
  • Drink and eat high-potassium foods like fruit juices and nectars, sports drinks, potatoes with the skin and bananas.
  • Do not chew sugar-free gum or eat candies and desserts made with sugar alcohols such as sorbitol, mannitol and xylitol.


Belly-Soothing Banana Smoothie

1 cup water
1 cup frozen bananas
1 tbsp. honey
½ tsp. vanilla powder
½ tsp. cinnamon
Pinch of salt

Place all ingredients in a blender, process until smooth and creamy.

Pineapple Ginger Smoothie

1 frozen banana
1 cup fresh pineapple
½ cup 2% or nonfat plain Greek yogurt
¼ cup unsweetened almond milk
½ tsp. fresh grated ginger or ¼ tsp. ground ginger
½ tsp. ground turmeric
2 tsp. chia seeds
Optional: A few fresh mint leaves

Blend all ingredients.


Contact your physician if:

  • You have diarrhea, stomach pain and dizziness that lasts more than a day.
  • You have a fever of 100.5 degrees F or higher.
  • Your stools have an unusual odor or color.
  • Your rectal area is sore and bleeding.

Ask about medicines that can help.


  • Academy of Nutrition and Dietetics
  • American Cancer Society
  • American Institute for Cancer Research
  • National Cancer Institute