In selected chapters of the therapeutic endoscopy we tried to represent secure knowledge, actual tendencies and partly future prognoses. Hereby completeness cannot be expected. However, it became clear that numerous physical principles became useful for the therapy with the endoscope. Chemical techniques, such as the litholysis of gall-stones are only at present used in our field. With all scepticism against the own field of interest one may say that the operative therapeutic endoscopy, as it is seen at the instance of the classification of polyps, has led to an improvement of the diagnostics, Its advantages in the therapeutic field are based on the fact that it substitutes larger operations. In the polypectomy- the intervention, avoiding laparotomy and colotomy, is reduced on the minimum given by the size of the polyp. The risk of endoscopic operations is small, compared with the alternative surgical interventions. Shortening of the duration of the disease and hospitalisation leads to lower expenses. Methods, such as the endoscopic haemostypsis or the obliteration of the pancreatic duct, need further detailed examinations. There is no doubt that the modern endoscopy has a strong technical fascination for many young physicians. It gets the greatest value in the hands of a clinically experienced physician.