Colorectal cancer (CRC) poses still a threat for a substantial part of general population. Its secondary prevention is based on one of four currently available screening methods: fecal occult blood test, sigmoidoscopy, combination of both these methods, and colonoscopy. As the efficacy of the screening is still limited, investigators seek for effective and safe chemoprophylaxis. Aspirin and other non-steroidal antiinflammatory drugs, as well as several other substances have been shown to have anticancer properties in large bowel. However, the risk of adverse effects and equivocal efficacy limits the practical usefulness of chemoprevention to two conditions, both associated with high risk of CRC – familial adenomatous polyposis and long-term ulcerative (or Crohn’s) colitis. The general population at only average or mildly increased risk should rely on screening. When this suplemmented by increased consumption of dietary fiber, micronutrients and vitamins, it can be assumed as a safe and potentially effective chemoprophylaxis.

        Key words: colorectal cancer, screening, chemoprevention, non-steroidal antiinflammatory drugs.