A polyp is a protrusion from the lining of the bowel, caused by an abnormal multiplication of cells. It may be a local raised area, look like a grape with a narrow stalk, or take the form of many fine projections, resembling the pile of a carpet. If not removed, some types of polyp may grow and eventually lead to cancer. Removal of a polyp or polyps is a good way of reducing the risk of bowel cancer.
Most polyps cause no symptoms.
Sometimes they bleed easily and the blood can be seen mixed with the stool or on its surface. A polyp may also secrete clear mucus which is passed with the stool. Very rarely, a polyp can cause a partial or complete blockage of the bowel which leads to unexpected constipation or diarrhoea with abdominal pain, bloating and, in severe cases, vomiting. Polyps are usually found during two types of test. First, an endoscopy which involves passing a flexible telescope up from the anus.