Woman in olive green holding a bowl of oatmeal with raspberries.
Tips for Side Effects, Nutrition

Managing Constipation Through Cancer Care

While it may be difficult to talk about, constipation is a rather common and uncomfortable side effect of some types of cancer treatment.  

Defined as having three or fewer bowel movements per week, constipation often involves stool that is hard and difficult to pass. Bowel movements may also feel incomplete and cause a feeling of fullness that can make it more difficult to eat. 

Though a variety of things may contribute to constipation, common causes during cancer treatment include the following: 

  • Decreased fiber intake 

  • Inadequate hydration 

  • Less physical activity 

  • Pain medications 

  • Some anti-nausea and antidepressant medications


A Combined Approach: Nutrition, Supplements, and Medication

Managing constipation often requires a combination of food-based strategies, hydration, and medications (discussed below). It’s important to communicate with your clinical team if you’re experiencing constipation as it’s easier — and more comfortable — to treat constipation right away rather than waiting to see if things improve.

Keep Up Your Fluid Intake and Activity

When you can, aim for at least 8 cups of water and other fluids per day and move your body daily, to the best of your ability. You may find that sipping on herbal senna tea, such as Smooth Move tea by Traditional Medicinals, or drinking warm prune juice can be especially helpful to ease constipation. If you’re experiencing bloating or gas, avoid carbonated beverages, chewing gum, hard copy, and drinking from a straw because these lead to swallowing more air.

Consider Fiber Supplements

Some people benefit from adding fiber supplements to their daily routine.  Examples include Benefiber and Citrucel. Start with one dose daily mixed with 8 oz of water or other fluid, increasing every 2-3 days to a maximum dose of three times per day. Speak to your healthcare team for guidance specific to your situation.

Medications for Constipation are Available

Medications used to treat constipation include stool softeners, which pull water into the intestines to make stool easier to pass, and laxatives, which stimulate bowel movements. Bowel medications work in different ways and are often used in combination. It’s common to take stool softeners and laxative medications daily to prevent constipation during some phases of treatment. Speak to a member of your Iris Care Team for guidance on using stool softeners and laxatives and take only as directed.

Choose Fiber-Rich Foods

Eating fiber-rich foods helps to prevent constipation. but this can be challenging if you’re already struggling to eat due to the side effects of treatment. Fiber is found in plants, so increasing your intake of fruit, vegetables, whole grain breads, crackers and cereals, brown rice, quinoa, legumes, nuts, and seeds whenever possible is helpful.  

Here are some tips to increase fiber in your meals and snacks

  • Choose whole or dried fruit instead of juice. 

  • On labels of bread, cereal, and crackers, look for the word “whole” in the first ingredient, such as “whole wheat flour” and “whole grain oats.”  

  • Look for foods labeled as “high fiber,” which means at least 5 grams of fiber per serving; a “good source of fiber” contains at least 2.5 grams of fiber per serving.  

  • Choose brown rice, quinoa, or whole wheat pasta as your starch for meals. High-fiber pastas made with beans and lentils are also available. 

  • Mix flax meal, wheat germ, unprocessed wheat bran, chia seeds, or cacao nibs into cereals, whole grain side dishes, smoothies, and salads to boost their fiber content.  

  • Blend beans into rice dishes, salads, and wrap sandwiches. Snack on hummus and sliced vegetables. 

  • Add nuts to hot or cold cereals, yogurt, and salads; spread nut butter on crackers and toast.


How Much Fiber Do We Need to Eat?

The USDA recommends 25 grams of fiber a day for women and 38 grams of fiber per day for men (up to age 50). Women and men older than age 50 need 21 and 30 grams of fat per day, respectively. These are general guidelines, however, which may need to be adjusted based on your baseline digestive health, type of cancer and treatment, and any side effects you may be experiencing.  

A few things to consider if you want to increase your fiber intake:  

  • Add fiber gradually to give your intestines time to adapt. Sudden increases in fiber intake can contribute to bloating and changes in bowel movements.  

  • As you eat more fiber, it’s also important that you’re drinking enough liquids.  

  • An Iris Registered Dietitian and Licensed Nutritionist can help you determine how much fiber and fluid you need.


Examples of High-Fiber Foods and Fiber Content Per Serving:


Grams of Fiber 

Raspberries (1 c) 

Prunes, stewed (1/2 c) 

Pear (1 medium) 

Figs, dried (1/4 c) 

Apple (1 medium) 

Strawberries (1 cup) 

Orange (1 medium) 

Banana (1 medium) 


Grams of Fiber

Lentils (1/2 c) 

Chickpeas/kidney beans (1/2 c) 

Peas (1/2 c)  

Carrots (1 c raw) 

Broccoli (1 c ) 

Winter squash (1/2 c) 

Cauliflower (1 c)  

Corn (1/2 c)  

Potato with skin (1 medium) 




Grams of Fiber

Shredded wheat (1 cup) 

Fiber One (1/2 c) 

Bran flakes (1 c)  

Oatmeal (1 c) 

Flaxseed, ground (1 Tbsp) 

Wheat germ (2 Tbsp)


Grams of Fiber

Quinoa (1 c) 

Brown rice (3/4 c) 

Whole wheat pasta (1 c) 

Popcorn (3 c)



Grams of Fiber

Peanuts (1/4 c)   

Walnuts (1/4 c) 

Sunflower seeds (2 Tbsp)

If you’re experiencing constipation or would like help with your nutrition plan, the Iris Care Team is available to discuss your options.

This article meets Iris standards for medical accuracy. It has been fact-checked by the Iris Clinical Editorial Board, our team of oncology experts who ensure that the content is evidence based and up to date. The Iris Clinical Editorial Board includes board-certified oncologists and pharmacists, psychologists, advanced practice providers, licensed clinical social workers, oncology-certified nurses, and dietitians.