Trainees (Residents in internal medicine), naive to real patient endoscopy, will be randomized to receive either 3 weeks/2 hours per day of structured training for a total of 20 hours on the virtual endoscopy simulator GI-Mentor or no training before starting on-patient endoscopy in the University of Vienna Medical School Endoscopy Unit. Patients satisfaction and pain, technical accuracy and number of found/missed pathologies as well as average time for successful endoscopy will be recorded. After one month or 50 supervised, self performed endoscopies, trainees will be evaluated again with the above mentioned criteria during ten consecutive investigations.