The medical implant for treating pathological obesity is adapted to modify and, as an alternative, to bypass the natural food passage in the digestive tract. The implant permits an adjustable bypassing of food into the small intestine and/or into the stomach (natural digestive path). Since the ratio of this bypass is adjustable in the course of the treatment by the physician, e.g. with the aid of an endoscope, for the first time a balance between the therapeutic effect and the side-effects can be adapted individually to each patient by the use of the implant. The implant has a hollow body with first and a second tubular end portions and at least one third lateral opening having a hose-like extension. The individual at least partly closable hose-like extensions differ in their ability to allow the passage of food into the stomach. Closing individual hose-like extensions at least partially by means of an endoscope leads to an individually adjustable distribution of food between the stomach and the small-intestine loop.