Tenesmus
What is tenesmus?
Tenesmus is the feeling that you need to go to the toilet but your bowel is empty. It can involve straining, pain and cramping. It can be caused by cramps (spasms) in the muscles that stimulate the bowel.
Tell your doctor or nurse if you have these symptoms.
What causes tenesmus?
Tenesmus can be caused by changes to the rectum (back passage) after radiotherapy or surgery. Sometimes it can be a symptom of another problem, including:
- constipation
- infection
- a non-cancerous growth called a polyp
- cancer in the bowel.
Test for tenesmus
If you have tenesmus, your doctor will examine your rectum. They may arrange for you to have a test called a colonoscopy or flexible sigmoidoscopy. This is where a doctor or nurse passes a thin tube with a light and tiny camera on the end into the bowel to look for any abnormal areas.
Tenesmus treatment
If your symptoms are a late effect of bowel cancer treatment, your doctor may suggest:
- pelvic floor exercises
- a toilet routine
- using the correct toilet posture - this means sitting on the toilet in the right position
- taking soluble fibre to bulk up the stool (poo), or a fibre supplement such as Normacol®
- low doses of certain anti-depressant drugs to reduce the sensitivity of the rectum.
About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
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References
Below is a sample of the sources used in our late effects of pelvic radiotherapy information. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk
K Mueller K, A Karimuddin, C Metcalf, et al. Management of malignant rectal pain and tenesmus. Journal of Palliative Medicine 2019. Available at https://med-fom-fpit.sites.olt.ubc.ca/files/2020/09/Mueller.pdf [accessed March 2026]
S Haas, A Højer Mikkelsen, C Jensenius Skovhus Kronborg et al. Management of treatment-related sequelae following colorectal cancer. PubMed. Colorectal Disease Journal. 15 August 2022. Available at https://pubmed.ncbi.nlm.nih.gov/35969031/ [accessed March 2026]
A Carlile and T McAdam. The Long-Term and Late Effects of the Diagnosis and Treatment of Colorectal Cancer. Ulster Medical Journal. 2023 May. Available at https://pubmed.ncbi.nlm.nih.gov/37649914/ [accessed March 2026]
V Sun, C Wendal,W Demark-Wahnefried et al. Diet and Behaviour Modifications by Long-Term Rectal Cancer Survivors to Manage Bowel Dysfunction-Associated Symptoms. PubMed. Nutrition and Cancer. 2020 January. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6456395/ [accessed March 2026]
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