Sedation in connection with oesophago-gastro-duodenoscopy is carried out in various ways. The investigation may be carried out with surface anaesthesia in the pharynx in well-informed and mentally stable patients but accept of renewed endoscopy is increased significantly when sedation is employed. Patients with an absolute requirement for sedation may be selected possibly employing a brief personality test. Employment of diazepam is extensively employed but diazepam interacts with cimetidin among other drugs, has a relatively long half-life and can cause secondary sedation. Midazolam has a more rapid effect, a briefer half-life, provides deeper sedation and results in more amnesia than diazepam. The oxygen tension decrease during endoscopy regardless of the sedative employed. Other sedatives, opioids, atropin or anaesthetics are not indicated under normal circumstances. Sedation can be abolished immediately after endoscopy with the bendzodiazepin-antagonist, flumazenil.