In Taiwan, the incidence of colorectal cancer is increasing as lifestyles and diets have become more westernized. There is a tendency for more young cases, while the incidence is higher in urban areas than in rural areas. Studies have shown that some environmental factors are associated with the development of colorectal cancer, including intake of fiber or vegetables, alcohol, and physical activity. In the United States, by contrast, the incidence of colorectal cancer is declining because of advances in cancer screening. The importance of cancer screening cannot be overemphasized.