A blocked bowel (bowel obstruction)

A bowel obstruction means there is a blockage in the bowel. It is a serious complication, which is much more common with advanced cancer. 

About bowel obstruction

Your bowel might become completely or partly blocked. This means that the waste from digested food can't get past the blockage. The diagram shows the bowel and the rest of the digestive system.

Diagram showing the position of the small bowel in the digestive system

Bowel obstruction can happen when:

  • cancer in the abdominal area (such as ovarian, bowel or stomach cancer) presses on the bowel
  • other cancers (such as lung or breast cancer) spread to the abdomen and press on the bowel
  • cancer grows into the nerve supply of the bowel and damages it - this can stop the muscles working
  • a solid mass of indigestible material collects in the bowel (called a bezoar)

Bowel obstruction is much more common with advanced cancer. People who have had surgery or radiotherapy to the tummy (abdomen) are more at risk of developing a bowel obstruction. 

Symptoms of bowel obstruction

The symptoms include:

  • feeling bloated and full
  • pain (usually colicky tummy pain)
  • feeling sick
  • vomiting large amounts (including undigested food or bowel fluid)
  • constipation (shown by not passing wind and no bowel sounds)

Diagnosing a bowel obstruction

Your doctor will examine you and ask you questions. They will then arrange some tests and investigations. These might include blood and urine tests.

You may also have an abdominal x-ray. Or you might have a barium enema to find out exactly where the obstruction is in your bowel.

Treating a bowel obstruction

It’s important to understand what your doctors are trying to achieve with any treatments they recommend. So talk it through with them or with your specialist nurse.

Treatments for a blocked bowel can include:

Drips and drains

Your doctor might suggest treatment to give your bowel time to rest. You need to stop eating and drinking until your bowel is working normally again. You may need fluids through a drip so you don’t get dehydrated. This is called an intravenous infusion.

Sometimes you can have an infusion of fluids at home. You have this through a fine needle put just under the skin, instead of into a vein.

This may fix the blockage. But if it isn’t successful, you may need other treatments.

You might have a tube that goes up your nose and down into your stomach (called a nasogastric tube). This drains fluid from your stomach and stops you feeling sick.

Or your doctor might suggest that you have a venting gastrostomy to help relieve nausea and vomiting. This is when they put a special tube called a percutaneous endoscopic gastrostomy tube (PEG tube) into your stomach through an opening made on the outside of your abdomen. You usually have this under sedation.


If your cancer is advanced and cannot be cured your doctor might suggest surgery to offer you longer term relief from your symptoms. The surgeon removes enough of the cancer to unblock the bowel. They might remove part of the bowel as well. 

After the operation your surgeon is most likely to repair the bowel by stitching the ends back together. But sometimes it isn’t possible to do this and you may need to have a colostomy or ileostomy (stoma). A stoma is an opening from the bowel onto the abdomen. Your poo comes out of this opening into a plastic bag that sticks over it.

Deciding whether to have an operation like this can be difficult. 

The surgery won't cure your cancer. But it can relieve the symptoms that you have. Unfortunately, no one can tell beforehand how much you will benefit from an operation to unblock your bowel.

The operation could be successful and the cancer might not grow back to block the bowel again. But it is quite a big operation to have when you are likely to be feeling very weak and ill.

You might want to talk through having this operation with your close family and friends as well as your doctor and nurse.

A stent

A stent is a tube that the surgeon puts into the bowel. It expands to keep the bowel open. This can relieve the symptoms caused by the obstruction.

Your surgeon may be able to put in a stent if you are not able to have a big operation. 


Instead of an operation, medicines can sometimes help to control symptoms of a blocked bowel. Unfortunately these types of treatment will usually only control your symptoms for a while.

A drug called hyoscine butylbromide (Buscopan) stops muscle spasms and reduces pain. You can also have painkillers and anti sickness medicines.

You might also have a drug called octreotide. Octreotide reduces the amount of fluid that builds up in your stomach and digestive system. It can help to control sickness.

Or you might have steroids. Steroids can help to reduce the inflammation of your bowel. They can also help to control sickness. 

Last reviewed: 
08 Aug 2019
  • Acute large bowel obstruction
    National Institute for Health and Care Excellence (NICE), 2011

  • Electronic Medicines Compendium
    Accessed August 2019

  • Palliative Venting Gastrostomy in Patients with Malignant Bowel Obstruction and Ascites
    Colette Shaw and others
    Annals of Surgical Oncology, 2013 Feb; 20(2): 497–505

  • Diagnosis, assessment and management of constipation in advanced cancer: ESMO Clinical Practice Guidelines

    P.J Larkin and others

    Annals of Oncology, 2018. Vol 29, Supplement 4.

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