The invention relates to a process for stabilising an aqueous preparation against microbial growth, the aqueous preparation stabilised against microbial growth as well as the use of a source of at least one metal oxide and/or its hydrated form for reducing the amount of an antimicrobial agent against at least one strain of bacteria and/or at least one strain of yeast and/or at least one strain of mould in an aqueous preparation, the use of a composition comprising at least one antimicrobial agent and a source of at least one metal oxide and/or its hydrated form as an antimicrobial composition in an aqueous preparation, the use of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, half burnt dolomite, burnt dolomite, beryllium oxide, beryllium hydroxide, strontium oxide, strontium hydroxide, barium oxide, barium hydroxide, and mixtures thereof for increasing the pH of an aqueous preparation to a pH of above 8 and the use of an aqueous preparation stabilised against microbial growth in paper, plastics, polymer compositions, paint, coatings, concrete and/or agriculture applications.
