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Symptoms of colon cancer

The symptoms of colon cancer may include:

  • blood in or on your poo (stool), or bleeding from the back passage (rectum) – the blood may be bright red or dark
  • a change in your normal bowel habit that happens for no obvious reason and lasts longer than three weeks – for example, diarrhoea or constipation
  • unexplained weight loss
  • pain in your tummy (abdomen) or back passage
  • feeling that you haven’t emptied your bowel properly after you poo
  • unexplained tiredness, dizziness or breathlessness
  • a lower than normal level of red blood cells (anaemia).

Sometimes the cancer can cause a blockage (obstruction) in the bowel. You may feel constipated and bloated, be sick (vomit), and have tummy pain.

These symptoms can be caused by conditions other than colon cancer, but you should always have them checked by your doctor.

If you have symptoms that don’t improve within a few weeks, or if your symptoms get worse, it is important that you are referred to a specialist. They can do tests to find out what the problem is.

Back to Understanding colon cancer

What is cancer?

There are more than 200 different kinds of cancer, each with its own name and treatment.

The bowel

The bowel is part of our digestive system and is made up of the small bowel and the large bowel.