A barium enema is a test that helps highlight the bowel, so it can be clearly seen on an X-ray. A white liquid is passed into your bowel through your bottom.

It allows doctors to investigate problems such as:

• bowel cancer
• cancerous or non-cancerous growths (bowel polyps)
• inflammation of the lining of the large bowel (ulcerative colitis or Crohn's disease)
• pouches arising from the large intestine (diverticular disease)

When you may be referred for a barium enema

Your GP may suggest a barium enema if you have noticed blood in your stools or if you have an unexpected change to your bowel movements, such as diarrhoea or constipation.

It may also be used if you have a family history of colorectal polyps or colorectal cancer and you have unexplained lower abdominal pain.

A CT scan or a colonoscopy (a type of endoscopy) are alternatives to a barium enema.

A barium enema examination is not advisable if you are pregnant because you will be exposed to some radiation. The amount of radiation is considered safe for the patient but could be dangerous for an unborn child. Read more about the risks of a barium enema.

What happens during a barium enema

The examination will either be done by either:

• a radiologist – a doctor with expertise in medical imaging
• a radiographer – a healthcare professional specially trained to produce medical images

A liquid called barium sulphate is passed into your bowel through a small soft tube inserted into your bottom. The liquid coats the inside of your bowel so that it can be clearly seen on an X-ray.

At the same time, air is usually pumped through the tube to expand the large bowel. This helps to make the images as clear as possible.

The whole process of injecting the fluid and taking the required X-rays takes around 30 minutes. It should not be painful but can cause some discomfort and bloating, mainly due to the large bowel stretching when the air is pumped in.

You are usually given an injection of a medication called Buscopan during the examination. This can help relieve any cramping sensation and improve the pictures.

The X-ray images are analysed by a radiologist or radiographer after the appointment. A report is given to your doctor, usually within 14 days.

Read more about how a barium enema is performed.