Dealing with Chemo Side Effects: Constipation and Diarrhea

When it comes to chemotherapy’s effects on the gastrointestinal tract, nausea has always gotten top billing. Unfortunately, chemotherapy’s side effects extend throughout the GI tract, and can cause constipation—and sometimes diarrhea—in many people as well.

Countering Constipation

“Constipation definitely happens to many patients,” affirms Dr. Stephanie Wethington, gynecologic oncologist at Johns Hopkins Medicine in Baltimore. She explains that constipation can be a side effect of the chemotherapy drugs themselves, or it can be a result of debulking surgery that often involves the bowel and then necessitates dietary changes. Constipation can also be a result of the changes people make to their diet after their taste and appetite are affected by chemotherapy.

No matter what the cause, the steps that help to combat it are the same: Staying well hydrated, eating a diet full of vegetables and fiber, and using over-the-counter laxatives and stool softeners when necessary.

Eating probiotic foods or taking probiotic supplements may also help, although research is still ongoing to find out whether these foods and supplements full of helpful bacteria can work to regulate the gut and ease symptoms of diarrhea or constipation. Probiotic foods include yogurt and fermented foods like pickles and kimchi. Research is still ongoing to find out whether probiotic foods and supplements can help regulate the gut and ease symptoms of diarrhea or constipation. Probiotic foods include yogurt and fermented foods like pickles and kimchi. Some studies seem to indicate that supplements containing Bifidobacterium can help ease constipation. Some studies seem to indicate that supplements containing Bifidobacterium can help ease constipation.

One other thing that can help: persistence. “You need to slowly try one thing, or one change, and give it a chance to work.  And then once you get to that good place where everything is working, don’t stop,” says Dr. Wethington. “You’ve got to keep on your regimen because the constipation will come back if you don’t. She advises starting with dietary changes and hydration, and moving on to over-the-counter laxatives or stool softeners—after talking to your doctor—only if those lifestyle steps don’t work.

Dealing with Diarrhea

“The side effect of diarrhea with chemotherapy for ovarian cancer is less common than constipation,” says Dr. Wethington. “But it does occur. And like constipation it also can be addressed with a combination of diet and over-the-counter medications.”

The diet that doctors recommend for diarrhea is called the BRAT diet, with the letters standing for bananas, rice, applesauce, and tea—all foods and drinks that are gentle on the stomach and easy to digest. The diet is low in protein, fat, and fiber, which makes them easy to digest. But because the BRAT diet is so limited in food groups and nutrients, it shouldn’t be followed for more than a few days. There are other bland foods that are easy on the stomach and can be easily digested and added to the BRAT diet. These include saltine crackers, oatmeal, plain potatoes and sweet potatoes.

And because so much fluid is lost from the body with diarrhea, it’s important to stay hydrated with fluids like water, tea, apple juice, and clear broths.

Over-the-counter medication like Imodium can also help. But when diarrhea persists, it’s important to have infectious causes ruled out, as a bacterial or viral infectious might require a more specific treatment.

Patience and persistence seem to be the key to dealing with either unpleasant side effect of chemotherapy for ovarian cancer: constipation or diarrhea. Consistent dietary changes, good hydration, and medication when needed can help vanquish both conditions.

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