Chemotherapy and Constipation

Prevention and Treatment

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Constipation is a common side effect of chemotherapy or other medications prescribed during cancer treatment. Constipation is defined as having hard or infrequent stools or difficulty in having a bowel movement.

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Many people are familiar with the symptoms of constipation. These can include abdominal cramping, a sense of fullness in the abdomen, rectal pain, and of course, you may notice that you haven't had a bowel movement for 2 or 3 days if you are usually regular. The symptoms, however, are not always obvious to those going through chemotherapy or coping with other medical conditions. They may include only a decrease in appetite and a vague feeling of being unwell—symptoms that are common with cancer, to begin with.


Several different factors can lead to constipation during chemotherapy. These include:

  • Chemotherapy drugs
  • Drugs used to treat nausea and vomiting
  • Decreased activity and bed rest
  • Pain medications
  • Elevated calcium level in the blood (hypercalcemia of malignancy)
  • Dehydration
  • Thyroid problems


Most of the time the diagnosis of constipation during chemotherapy can be determined based on symptoms alone in combination with medications that raise the risk.


The first thing you should do is talk to your healthcare provider. Tell him that you are experiencing constipation or hard/infrequent stools. Your healthcare provider will likely want to know about your eating habits if you have taken any over-the-counter laxatives, enemas, or suppositories, and confirm medications you are taking. It helps to be especially thorough when listing your medications to your healthcare provider because many medications used in cancer treatments and pain relief can cause constipation. These questions will help determine the exact cause of constipation.

Fluid Intake

Many patients report some relief when increasing the amount of fluids they drink. Drinks like water and juices are recommended. Avoid drinks that contain caffeine, (like sodas or coffee) and alcohol, because they can cause dehydration, which could worsen constipation.

Dietary Fiber

For mild cases of constipation, increasing fiber in the diet can be all the body needs to have regular bowel movements. Before increasing fiber in the diet, ask your healthcare provider. Some patients should not have increased fiber, such as those who have had a bowel obstruction or bowel surgery.

Increasing the amount of fiber starts with the foods you eat. Nuts, bran, vegetables, legumes, whole wheat bread, pasta, and many fruits and vegetables are all high-fiber foods that can help prevent constipation. In a 2016 study, sweet potatoes were found to be particularly effective in preventing constipation.

Once someone is very constipated, adding in high-fiber foods may increase discomfort until constipation has been relieved.

Talk to your healthcare provider about how much fiber you should be getting daily. The suggested dietary intake for healthy women is 21-25 grams and men should consume 30-38 grams per day. You can find out how much fiber is in a certain food by reading the label on the packaging or looking it up online in the case of foods that aren't labeled such as fruits and vegetables.


Exercise is still very important when going through treatment. Something as simple as going for a short, regular walk can help to prevent and relieve constipation. For those who are bedridden, moving from a chair to the bed can help because it utilizes the abdominal muscles

Before starting any exercise, no matter how little you think it may be, talk to your healthcare provider. He or she can recommend exercises and tell you just how much you should be getting.


Several categories of medications work for constipation in different ways. Some of these may work better than others for particular causes of constipation, so it's important to talk to your healthcare provider and get her recommendation. Some medications come with a combination of two or more of these drugs, designed to both soften the stool and aid in its evacuation.

With some chemotherapy regimens, the combination of drugs, especially drugs to prevent nausea, are very constipating, and your oncologist may recommend using medications for constipation preventively. Make sure to do so, as it is easier to prevent than treat severe constipation.

Also, make sure to talk to your oncologist before using any medications, as some of these have the potential to interfere with chemotherapy drugs.

Some treatments include:

  • Bulk-forming laxatives: These medications work to draw water back into the intestine to decrease the hardness of the stool, as well as by decreasing transit time—the amount of time that stool stays in the colon. An example of this category is Metamucil (psyllium).
  • Stimulant laxatives: Stimulants work directly on the nerves around the colon to stimulate the transit of stool through the gastrointestinal tract. Because it can be painful when very hard stools pass through the colon, these are often given along with a stool softener. Examples of stimulant laxatives include Senekot (senna) and Dulcolax (bisacodyl).
  • Osmotic laxatives: Osmotic laxatives work to keep fluids in the colon and also stimulate peristalsis—the rhythmic contractions of the colon that move stool forward. Examples include Chronulac (lactulose), glycerin suppositories, Miralax (polyethylene glycol), magnesium citrate and Milk of Magnesia (magnesium hydroxide).
  • Emollients/Stool softeners: Stool softeners soften the stool by working with the mix of water and fat in the stool. These medications soften the stool but do not decrease transit time, so they are often used along with another medication to facilitate a bowel movement if these have become infrequent. An example of these is Colace (docusate).
  • Lubricants: These medications bring water into the stool to soften it and also lubricate the stool for passage out of the body. Mineral oil is an example.

Manual Removal

When all else fails, if fecal impaction occurs, or if constipation is very painful, digital evacuation may need to be done. This refers to the manual removal of stool using gloved fingers.


Chronic severe constipation can lead to fecal impaction, a condition in which hard, dry fecal matter that develops in the rectum and cannot be passed. The impacted feces are then removed by the doctor manually.

Other complications from chronic constipation include hemorrhoids, anal fissures, perianal abscesses, and rectal prolapse.

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  1. Bashir A, Sizar O. Laxatives. In: StatPearls. Updated October 8, 2019.

  2. American Society of Clinical Oncology, Constipation. Updated December 2019.

  3. National Institutes of Health: National Cancer Institute. Gastrointestinal complications (PDQ®)–Patient version. Updated March 7, 2019.

  4. Zou JY, Xu Y, Wang XH, Jiang Q, Zhu XM. Improvement of constipation in leukemia patients undergoing chemotherapy using sweet potato. Cancer Nurs. 2016;39(3):181-6. doi:10.1097/NCC.0000000000000257

  5. Academy of Nutrition and Dietetics: EatRight. Easy ways to boost fiber in your daily diet. Updated September 5, 2017.

  6. Liu LW. Chronic constipation: current treatment options. Can J Gastroenterol. 2011;25 Suppl B:22B-28B.