Bowel cancer, also called colorectal cancer, is a malignancy arising in the colon or rectum, often developing from benign polyps on the intestinal wall that become cancerous over years. Symptoms include persistent changes in bowel habit, blood in the stool, abdominal pain, and unexplained weight loss. Risk rises with age, family history, and lifestyle factors: diets high in red and processed meat and low in fibre are associated with increased risk, while physical activity and adequate fibre appear protective. Screening programmes using faecal occult blood tests and colonoscopy catch early disease when treatment is most effective, making diet and screening central to prevention.