Colorectal cancer is the third most common cancer and the second most common cause of death from cancer in many industrialised countries. This disease will affect 5% of the US population, resulting in over 130 000 new cases and 57 000 deaths projected this year. The age adjusted death rates are highly variable in populations located in different parts of the world. For example, there are 3.4 cases per 100 000 in Nigeria compared with 35.8 cases per 100 000 each year in the state of Connecticut, USA. This indicates that, apart from the known genetic factors, certain environmental and dietary factors are probably involved in the aetiology of this disease. Epidemiological, clinical and genetic evidence indicates that a great number of colorectal adenocarcinomas develop from a benign adenomatous polyp progressing through a sequence of events which may take about 15–20 years.1 The progression of events leading …