A mixture of substances is designated for introduction into a liquid
aqueous system and comprises at least one extremely finely divided active
substance component that is designated for subsequent dissolution or
dispersion in the liquid aqueous system. The mixture of substances
comprises a proportion of cellulose-containing plant fibers and is
present in finely particulate form. The cellulose-containing plant fibers
improve both the transformation of the extremely finely divided active
substance component into the finely particulate form and also its
subsequent redissolution in the liquid aqueous system.