Multiple factors have been described among the causes of non-hereditary colorectal cancer. In Western countries, the most common risk factors include upper-middle socioeconomic status and dietary regimens rich in proteins and animal fats. High consumption of red meats, smoked foods, cold cuts, or canned foods is believed to contribute to carcinogenesis as they directly affect epithlial turnover and cause metabolism of biliary acids. Dietary fibers have protective effects in that they capture the fats and biliary acids, thereby inhibiting their activity. Tobacco smoking acts both locally and systemically on the colorectal mucosa through the production of carcinogenic agents. Finally, the action of alcohol, in association with nicotine addiction, also increases the risk of developing colorectal tumors. Knowledge of dietary and environmental factors is of paramount importance in implementing preventive strategies for colorectal cancer.