Abstract: A composite molecular active substance group for use in restitutive chemotherapy against viral infections, which is produced by the process comprising: (a) 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; (b) 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 (c) preparing a water-soluble mixed polymer by reacting the lignin units from step (a) with the lignoid units from step (b), 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 res