a composite molecular active substance group for use in restitutive chemotherapy against viral infections , which is produced by the process comprising : preparing lignin units by carrying out an extraction in an aqueous media under weakly acidic or alkaline conditions of wood or wood - like materials and / or plant - cell cultures and separating - off the resultant insoluble solids ; preparing lignoid units by carrying out an aqueous alkaline extraction at a ph of 7 to 14 of starting materials selected from the group consisting of wood - incarbonization products and bioconverted wood - like materials and separating - off the resultant alkali - insoluble solids ; and preparing a water - soluble mixed polymer by reacting the lignin units from step with the lignoid units from step , under aqueous alkaline isolating by ultrafiltration a low molecular weight fraction having a molecular weight of no more than 3000 daltons of the mixed polymer , taking a cut between 15 to 40 kilodaltons and discarding the resultant residue , and treating the resultant solution with an h + cation exchanger at a ph of 3 to 7 and then carrying out further processing .