Humans have two bowels, a large bowel (intestine) and a small bowel (intestine). In the large bowel, humans have a rectum and a colon. The Colon absorbs the water in our food like a sponge. The rectum (back passage) is where the waste is held until it comes out of our bodies. Most cancers in the bowels are found in the large bowl. Bowel or Colon cancer is when cells in the body keep on dividing when they should have stopped. This means that they cause a tumour.