A mineral mixture including at least' MgO and its equilibrium of Mg(OH)2, and MgCl2, in which MgO—Mg(OH)2 constitutes between 85 and 99.99% by weight; and MgCl2 constitutes between 0.01 and 15% by weight of the magnesium compounds in the mineral mixture. Preparations containing the salt mixture and the use of the mineral mixture for the production of a pharmaceutical preparation for the prevention or therapy of a condition, the condition being undesired eczema or psoriasis, are also described.