Abstract: According to the invention, a hydrogel comprising chemically modified polysaccharides and proteins is provided. Furthermore, a method is provided in order to produce a hydrogel from mixtures of polysaccharides and proteins. According to the invention, the polysaccharides and proteins are modified chemically covalently and crosslinked chemically intermolecularly by the method. The chemically derivatised polysaccharide-protein blend (abbreviated to “PPB”) which is produced according to the invention is characterised in that it forms a hydrogel in an aqueous medium. The PPB hydrogel according to the invention is characterised by a high water-binding potential and a high adhesive effect. For example in building chemistry, the PPB hydrogel according to the invention has an advantageous effect on the adhesion- and slippage behaviour of tiles.