Abstract: The invention provides a physiologically acceptable polymeric material having one or more ligands capable of binding to a receptor in a human or animal gut, said receptor being selected from the group consisting of carbohydrate, amino-acid, lipid and peptide receptors, characterised in that the polymeric material is substantially incapable of being absorbed by the gut, which is useful in the treatment of obesity or in the improvement of the bodily appearance of a human or animal by reducing its weight.