For the use of cardboard for food packaging the board has to meet certain requirements. The cardboard has to be odourless, tasteless, should have a low permeability for highly volatile food constituents e.g. flavours, but also has to have an insignificant permeability for components like printing inks, varnishes and solvents originating from the printing process. Folding boxboards without any special barrier coatings meet to these properties to a very limited extent. In order to meet these requirements the cardboard should be coated with a barrier material on its backside. The coating is in direct food contact and therefore has to be physiological safe. As the barrier protection should not be achieved through a laminated film, the material has to be cast on the cardboard from a solution or dispersion. It should be possible that the coated cardboard can be recycled. A number of water soluble polymers or waterborne dispersions were chosen for further characterisation, e. g. polypeptides, polysaccharides, solventless waterborne polymer dispersions, different polyvinyl alcohols or its copolymers or derivatives. These substances are cast on the cardboard with a paintbrush or a film applicator. Further characterisation includes the measurement of the film thickness, the weight per area and the weight loss by drying the specimen in an exsiccator. After the selection of a suitable coating method, a number of test specimens are prepared and their barrier properties determined.