A composition for a medical device is described. The composition comprises a specific mucoadherent gelling complex composed of EPS, exopolysaccharides of bacterial origin produced in situ in the gastrointestinal tract by specific selected bacterial strains, in association with vegetable gums and/or animal and/or vegetable gelatines. The complex is capable of establishing a complete barrier effect of a mechanical type extending throughout the whole gastrointestinal tract and can be used as a medication for the prevention and treatment of all pathologies connected to a deficiency in the barrier effect in the gastrointestinal area due to a low production of mucus, such as, by way of non-exhaustive example, intestinal permeability and bacterial translocation.