Bowel cancer awareness: Understanding your bowel

Your bowel (colon and bowel)

The bowel is a very important part of your body that helps you digest and absorb food and water. It extends from the stomach and stops at the anus. It is in two main parts – the small bowel (sometimes called the small intestine) and the large bowel (or large intestine). The large bowel is made up of the colon and the rectum.

The bowel is a tube that is made of a lining that absorbs food and water, and this is surrounded by muscle to help squeeze the food along.

Cancer of the small bowel is rare. Cancer of the large bowel is one of the most common cancers in New Zealand. If you have a family history of bowel cancer, talk to your doctor about your risk of bowel cancer and whether you should have regular surveillance or a colonoscopy.

If caught early, bowel cancer is very treatable.

The digestive system


Diagram showing the digestive system


How the bowel works

Food and liquid is broken down in the stomach. It is then digested in the small bowel, before passing into the large bowel. Here water and some nutrients are absorbed, leaving waste. Waste passes through the rest of the large bowel before leaving the body when you go to the toilet.

Looking after your bowel

Some 'everyday' things you can do that may reduce your risk of developing bowel cancer are:

  • Aim to be a healthy weight throughout your life. Weight gain, especially around the waist, is linked to bowel cancer.
  • Eat mostly plant foods: vegetables, fruit, grains, legumes and pulses.
  • Choose wholemeal and whole-grain breads and cereals.
  • Eat smaller and fewer servings of red meat and avoid processed meats.
  • Eat foods low in fat, salt and sugar.
  • Be physically active every day. At least one hour per day of moderate activity (a brisk walk) lowers your risk of bowel cancer, but vigorous activity (soccer or running) several times per week is likely to have an even greater benefit.
  • Limit alcoholic drinks to one drink for women per day, and two drinks per day for men. Or ideally don’t drink alcohol at all.
  • Don't smoke.

Bowel cancer screening

In New Zealand, a bowel cancer screening programme is being rolled out region by region for those without symptoms. 
The National Bowel Screening Programme is free for men and women aged 60 to 74 years who are eligible for publicly funded healthcare. It aims to save lives by finding bowel cancer at an early stage when it can often be successfully treated. 
For more information, talk to your doctor, call 0800 924 432, or visit the screening website: 

What you should look for


Early bowel cancer often has no symptoms

It is important to know what is normal for you so you can spot any changes. If you notice any of these symptoms and they last longer than four to six weeks, tell your doctor.

  • Bleeding from your bottom or blood in your bowel motion.
  • A recent change in your bowel motions: going to the toilet more often, diarrhoea, constipation or a feeling that your bowel does not empty completely.
  • Stomach pains, frequent wind pains, bloating or cramps.

These symptoms may not be caused by cancer, but it is important to play it safe and talk to your doctor. 

This information was published in August 2018 by the Cancer Society.