Abstract: The specification is directed to polysiloxane foams. There are disclosed compositions capable of curing at room temperature which comprise a hydroxypolysiloxane, an alkylhydrogen polysiloxane, a tin compound as catalyst and finely divided filler. According to the invention storage stability of these foam forming polysiloxane compositions is improved by use as filler of silica which has been pretreated to render is hydrophobic. The subject compositions may comprise two components which do not require individual mixing prior to mixing together of the components. The compositions may be packaged in any convenient manner. The compositions may be used for a variety of purposes, for example to provide medical dressings.