The proposal is for an active ingredient release system with optical endpoint display, comprising(a) a container for accommodating the components,(b) two solvents A and B located therein, which are immiscible or only minorly miscible with one another,(c) at least one active ingredient which serves as solubilizer for the solvents A and B, and(d) a mechanism which allows the release of the active ingredient, but restrains the other volatile constituents of the composition.
