At the practice of gastroenterologist-hepatologist Sotiria Bedreli, in Alexandroupoli, it is possible to diagnose lactose intolerance by taking a biopsy of the duodenal mucosa during a diagnostic gastroscopy. Symptoms such as bloating, abdominal pain, diarrhea, etc. are typical complaints in case of partial or total deficiency of the lactase enzyme, which is necessary for the metabolism of milk lactose and whose partial or total deficiency is determined directly through a biopsy of the duodenal mucosa.