Helicobacter pylori infection is a problem frequently handled by the gastroenterologist, but many other infections may cause symptoms and pathological findings which is of great significance for the endoscopist to recognize. Candida infection is the most common infection in the oesophagus. It may signal an underlying disease like diabetes. When the patient enters Norway from an area where tuberculosis is endemic it is necessary to be aware of possible abdominal tuberculosis. Immuno-compromised patients, and especially AIDS-patients, may have several dangerous gastrointestinal infections. The most frequent agents encountered in this situation include Cytomegalovirus, Mycobacterium avium intracellulare complex and Cryptosporidia. Treatment can be very problematic; both because of the underlying disease and because of the inefficacy of chemotherapy on the infectious agent.