Symptoms of constipation

Constipation means difficulty having a poo. It can be a problem for people with cancer and during cancer treatment. 

If you are constipated, you won’t have regular bowel movements (poo, stools or faeces). You might not have one for a few days or more.

The early symptoms of constipation can include:

  • difficulty and pain when passing a poo

  • fewer than 3 poo's a week

  • having to strain a lot when trying to open your bowels

  • hard, dry or lumpy poo that can look like small hard pellets or be unusually large

  • feeling that you have not completely emptied your bowel

  • feeling bloated and sluggish

Severe constipation

Severe constipation can cause more serious symptoms such as:

  • a swollen, hard tummy (with or without pain)

  • very liquid diarrhoea that you can’t control at all (overflow diarrhoea)

  • loss of appetite

  • feeling and being sick

  • headaches

  • confusion and feeling restless

  • being unable to pass urine (urinary retention)

What to do if you have constipation

Let your healthcare team know straight away if you think you are constipated. They can advise on diet and exercise. They might recommend medicines to help treat constipation.

Make sure that you get early treatment for constipation. It will make it much easier to sort the problem out. Leaving constipation for too long can lead to more serious problems such as a bowel blockage (obstruction).

  • Constipation
    National Institute for Health and Care Excellence (NICE), last reviewed June 2025

  • Diagnosis, assessment and management of constipation in advanced cancer: ESMO Clinical Practice Guidelines
    P J Larkin and others
    Annals of Oncology, October 2018. Volume 29, Supplement 4, Pages IV111 - IV125

  • A Guide to Refractory Constipation: Diagnosis and Evidence-Based Management
    M Corsetti and V Wilkinson-Smith 
    British society of gastroenterology, May 2020

  • BMJ Best Practice Constipation
    S Rao and D Shahsavari
    BMJ Publishing Group Ltd, last updated July 2025

  • Constipation
    World Cancer Research Fund
    Accessed September 2025

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact patientinformation@cancer.org.uk if you would like to see the full list of references we used for this information.

Last reviewed: 
17 Sep 2025
Next review due: 
17 Sep 2028

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