The invention relates to a prosthesis that is compressible and expandable in a radial direction, intended to be implanted in the digestive tract of a patient. According to the invention, such a prosthesis comprises: a downstream conical collar having end diameter D3, a main tabular body having diameter D2, an upstream conical collar having end diameter D1, said upstream collar not being covered by any material and having an end diameter D1 greater than the diameter D2 of said main body and greater than the end diameter D3 of said downstream collar, and said downstream collar being fully or partially covered by at least one polymer material.
