The environmental factor, pathogenic factor, host factor and others can be assumed as high-risk factors of colon carcinoma. Histopathologically, in most cases, colon carcinoma is recognized as an adenoma-carcinoma sequence that originates based on the adenoma. In this study, in addition to the adenoma and adenomatosis (familial polyposis, Gardner syndrome, Turcot syndrome), the hamartoma (Peutz-Jeghers syndrome, juvenile polyp), inflammatory bowel diseases (ulcerative colitis, Crohn's disease, fistel ani and others) and the origin of the carcinoma were examined. The oncogenesis based on the tubular adenoma, tubulovillous adenoma, villous adenoma and genetic adenomatosis of the large intestine could be found in many cases, thereby requiring a wide range of examinations and treatments. Concerning the oncogenesis of several kinds of inflammatory bowel diseases, much attention should be paid to diseases such as ulcerative colitis, Crohn's diseases, and fistel ani extending over a period of 10 years. In addition, it is necessary to study the connection and promotion among factors of the environmental, pathogenic and host factors.