Constipation
Constipation means having hard stools or going less often than usual. It can cause belly pain, bloating, and discomfort.
Why it happens
Opioid pain medicines and some anti-nausea medicines are common causes. Some chemotherapy drugs, such as vincristine, and less activity or fluid can add to it.
What helps
- Drink plenty of fluids during the day unless your care team has limited them.
- Add fiber slowly with fruits, vegetables, and whole grains, if your team says it is okay.
- Move your body each day, even a short walk helps.
- If you take opioid pain medicine, ask about a daily stool softener or laxative plan.
- Try to use the bathroom at the same time each day, like after breakfast.
Call your care team right away if you have
- You have not had a bowel movement in 3 days.
- You have belly pain, swelling, or vomiting with constipation.
- You cannot pass gas.
Questions to ask
- Which laxative or stool softener is right for me?
- Should I take something every day while I am on pain medicine?
- Are any of my medicines causing this?
Medicines that can cause this
- Alectinib
- Amivantamab
- Azacitidine
- Bendamustine
- Bortezomib
- Brentuximab vedotin
- Carboplatin
- Crizotinib
- Darolutamide
- Datopotamab deruxtecan
- Decitabine
- Elacestrant
- Elotuzumab
- Encorafenib and binimetinib
- Entrectinib
- Enzalutamide
- Eribulin
- Fulvestrant
- Gilteritinib
- Hydroxyurea
- Ixazomib
- Larotrectinib
- Lenalidomide
- Loperamide
- Lurbinectedin
- Mesna
- Mirvetuximab soravtansine
- Nilotinib
- Niraparib
- Olanzapine (for nausea)
Sources
Quick answers
- What is constipation during cancer treatment?
- Constipation means having hard stools or going less often than usual. It can cause belly pain, bloating, and discomfort.
- Why does constipation happen?
- Opioid pain medicines and some anti-nausea medicines are common causes. Some chemotherapy drugs, such as vincristine, and less activity or fluid can add to it.
- What helps with constipation?
- Drink plenty of fluids during the day unless your care team has limited them; Add fiber slowly with fruits, vegetables, and whole grains, if your team says it is okay; Move your body each day, even a short walk helps; If you take opioid pain medicine, ask about a daily stool softener or laxative plan; Try to use the bathroom at the same time each day, like after breakfast.
- When should I call my care team about constipation?
- You have not had a bowel movement in 3 days; You have belly pain, swelling, or vomiting with constipation; You cannot pass gas.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.