Abstract: The present invention relates to a method for preparing a preparation for bleaching teeth or for treating skin complaints and mucous membrane disorders, in which method at least the following are combined: (a) a gel or paste in which a component (i) is present, component (i) being composed of at least a cation A.sup.n+ and an anion O.sub.m X.sup.- ; where A is a metal from Group 1 or 2 of the periodic system, n=1 or 2, X is a halogen atom and m=1-4, and (b) a gel or paste in which a component (ii) is present, component (ii) being composed of at least a cation A.sup.n+ and an anion [B.sub.p O.sub.q ].sup.r-, where A is a metal from Group 1 or 2 of the periodic system, p=1-4, q=1-8 and r=1-3.