Silicic anhydride has conventionally and routinely been used as a gelling agent for silicones. In the present study, the mechanism wherein a crosslinked silicone having a specific crosslinking density is swollen in the presence of a silicone oil having a low viscosity to form a stable gel was applied to the manufacture of foundations, and optimum conditions that provide favorable functions and satisfactory organoleptic sensation were studied. Polymethylhydrogen siloxanes with a low crosslinking density were prepared by subjecting α,ω-divinyl polydimethyl siloxane to addition polymerization. The viscoelasticities of the gels formed by the resultant products and silicone oil were investigated. based on these results, it is concluded that the most suitable product is a low crosslinking density material obtained by adding α,ω-divinyl polydimethyl siloxane (M¯w: 1.0 kDa) to polymethyl hydrogen siloxane having an average molecular weight of 2.5 kDa under the conditions wherein the concentration of dimethylpolysiloxane (viscosity: 6 × 106 m2 S-1) is 60%. This product provides an enhanced viscosity at a reduced solids content. © 1997 John Wiley & Sons, Ltd.