Fecal calprotectin is a very sensitive non-invasive inflammation marker in the detection of inflammatory bowel disease and, to a lesser degree, has also proven to be useful in adenomatous polyps, neoplasias, and infectious gastroenteritis. Elevated calprotectin levels can also be found in patients with lesion only in the upper gastrointestinal tract. However, the diagnostic value of calprotectin has never been tested in this setting. The aim of the study is therefore to determine the diagnostic value of fecal calprotectin in patients with diseases of the upper gastrointestinal tract.