A variety of carcinogens, in particular smoking, alcohol abuse and infections, are associated with an increased risk for the development of cancer of the upper gastrointestinal tract. Cancer prevention should start here, in particular since cessation of nicotine abuse, only moderate consumption of alcohol, and weight loss also have other positive effects on health. Where the indication is appropriate, H. pylori eradication, vaccination against hepatitis B and avoidance of exposure to hepatitis are well-founded prophylactic measures. Further screening measures make good sense only in high-risk groups, and are based on recommendations. It has, however, not yet been demonstrated that the screening of patients with Barrett's esophagus, liver cirrhosis, chronic hepatitis or gastric risk diseases actually can lower cancer-related deaths.