Summary: Due to the development of modern gastrointestinal endoscopy, these techniques have become the gold standard in diagnosing gastrointestinal disease. Gastroscopy and colonoscopy are the most frequent endoscopic procedures. Appropriateness of referrals for upper and lower gastrointestinal endoscopy, as well as proper preparation for examination are important issues. The paper discusses preparation for endoscopic procedures and possible alterations in the treatment of chronic diseases before endoscopy.