Foods to Eat When You Have Diarrhea From Chemotherapy

Diarrhea is an extremely common side effect of chemotherapy. Digestive problems like diarrhea occur because of how chemotherapy drugs are designed to work. Cancer cells divide quickly — faster than most of the cells in our body. Chemotherapy drugs work by targeting these rapidly dividing cells.

At the same time, some normal cells in our bodies also rapidly divide. Our hair follicle cells and the cells in the lining of our stomach and digestive tract are some of the healthy cells that also divide rapidly. Chemotherapy drugs simply cannot tell the difference between these normal, rapidly dividing cells and cancer cells. Chemotherapy attacks your healthy rapidly diving cells as well. This is why we experience hair loss and digestive problems when undergoing chemotherapy.

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Diarrhea can quickly become serious, especially because it can quickly lead to dehydration. When you have runny bowel movements, you are losing a lot of fluids with each episode. The good news is that your healthcare provider can likely prescribe a medication to help prevent and treat diarrhea.

It is essential to report to your healthcare provider if you experience any side effects or health issues during your cancer treatment. Even if you suspect your symptoms are unrelated to treatment, be sure your healthcare team knows what is happening to your body.

This article discusses eating well and staying hydrated during chemotherapy. This is especially important if you are experiencing cancer or chemotherapy-related diarrhea.

Eating Well During Chemotherapy

Loss of appetite is very common and can occur anytime during treatment. Nausea and vomiting may make it hard to eat. Some chemotherapy drugs cause changes to your sense of taste and may make foods less appealing to you. Diarrhea or other digestive issues may reduce your desire to eat or drink.

One way to combat this lower intake is to try to take advantage of your appetite whenever you are hungry or thirsty. Remember to eat well-balanced meals that consist of lean protein, colorful fruits and vegetables, and lots of caffeine-free liquids. Your healthcare team may recommend that you avoid certain foods during treatment.

Eating well is essential during cancer treatment. It is especially important when you suffer from diarrhea. Some people find that there are foods that you can eat to help with diarrhea. The key is to consume foods that are low-fiber or that have pectin, a soluble fiber.

With diarrhea, you not only lose fluids (water), but you can lose electrolytes. Electrolytes are small particles with an electric charge. They are vital for your body to function. Some electrolytes include sodium, potassium, calcium, and magnesium. Eating foods rich in electrolytes helps replace what is lost when you have diarrhea.

What to Eat
  • Bananas

  • White rice

  • Noodles

  • Creamed cereals

  • Cottage cheese

  • Yogurt

  • Applesauce

  • Pear

  • Canned fruit without peels

  • White bread

  • Potatoes

  • Chicken breast

What to Avoid
  • Greasy or fatty foods 

  • Sugary foods

  • Dairy

  • Carbonated beverages

  • Beans

  • Nuts

  • Seeds

  • Cruciferous vegetables

  • Alcohol

  • Coffee

  • Tea

  • Artificial sweeteners

The BRAT diet is recommended by the 2016 National Comprehensive Cancer Network guidelines. The Bland Diet, also called the BRAT Diet, can sometimes help manage diarrhea. BRAT stands for bananas, rice, applesauce, and toast. These foods are believed to be gentle on an upset stomach and help firm stools.

Hydration is Key

As mentioned above, when you have diarrhea, you lose vital fluids with each bowel movement. Replacing those lost fluids is essential and should be done by drinking clear fluids in addition to your recommended daily water intake.

Gatorade, Powerade, and even Pedialyte are excellent rehydration fluids because they contain glucose and sodium to help regain adequate electrolyte levels.

Your healthcare provider may advise against drinking additional plain water to replace lost fluids. Too much plain water may decrease the body's sodium and calcium levels. This can result in electrolyte imbalances which can be life-threatening.

You may find that your digestive system is very sensitive right now. The sensitivity may continue throughout your treatment. Even if your appetite has not changed, you may find that certain foods now upset your stomach, even if they did not before treatment.

Summary

Diarrhea can be a common side effect of chemotherapy treatments. Eating foods that are gentle for your stomach may help. You may need to replace lost liquids to be able to stay hydrated.

Your healthcare provider may be able to recommend specific foods to eat and others to avoid to help reduce your diarrhea. In some cases, they can prescribe medications to help limit diarrhea.

A Word from Verywell

For many people, diarrhea is a problematic side effect of cancer treatment. It can be difficult to be far away from a toilet or to have little control over your bowel movements. Focus on replacing fluids after each time you use the bathroom. While dealing with diarrhea, it may help to eat small, frequent meals rather than larger ones. Your healthcare team is available to help you manage the side effects of treatment, so be sure to reach out if you experience diarrhea.

Frequently Asked Questions

  • Why does chemo give you diarrhea?

    Chemotherapy works to kill the fast-growing cells in your body. Chemotherapy drugs do not select between cancer cells and healthy cells. This means that they affect the tissues of your digestive system. When those gut cells die, they shed and can cause diarrhea.


  • Does fasting help with diarrhea?

    The American Academy of Family Physicians reports that a certain kind of chronic diarrhea called functional diarrhea gets better when you are fasting (not eating). However, there is currently no evidence that fasting improves chemotherapy-induced diarrhea.

  • How long does chemo induced diarrhea last?

    Diarrhea related to cancer treatments will be different for each person. The medication, dose, and length of treatment may all play a role in your symptoms. Once you are done with your chemotherapy or radiation treatments, diarrhea will normally start to improve. According to the American Cancer Society, it may last weeks or months after the final treatment for some people.

Originally written by Lisa Fayed
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Cancer Institute. Gastrointestinal complications (PDQ)—patient version.

  2. American Cancer Society. Diarrhea.

  3. Oncology Nursing Society. BRAT Diet for chemotherapy-induced diarrhea.

  4. American Academy of Family Physicians. BRAT diet: Recovering from an upset stomach.

  5. American Academy of Family Physicians. Chronic diarrhea.