The present invention pertains to a method for the in situ preparation of a filler, comprising the step of applying a polyanionic biopolymer solution at an application site below the dermis of a patient for restoring volume at said application site, wherein the polyanionic biopolymer is selected from pectin and gellan. Furthermore, the present invention pertains to a kit comprising (i) a polyanionic biopolymer solution and (ii) a solution comprising at least one divalent cation.
