To provide a stock solution for making foam (a mass of fine bubbles) chiefly utilized in the fields of cosmetics, qausi-drugs, domestic articles, and sundries.

Casein is adopted as a foaming agent of a natural origin. A research experiment has determined conditions for making good foam by using casein. The stock solution is applicable by a pump foamer or as an aerosol when it has a casein concentration in the range of 0.1 to 20wt.%. The addition of 0.01 to 5 wt.% aliphatic higher alcohol/aliphatic higher fatty acid and 0.4 to 25 wt.% 2-6C monohydric or polyhydric alcohol is effective to improve the properties of the foam.