The present invention provides a denture adhesive liner in the form of an extruded film or sheet, comprising a denture adhesive effective amount of alginate; thermoplastic polymer; and plasticizer, wherein said composition is extrudable into a film that is capable of adhering to a wet mucous surface. The present invention also provides a method for preparing a denture adhesive liner comprising the steps of: preparing a composition of a denture adhesive effective amount of alginate; thermoplastic polymer; and plasticizer; and forming a denture adhesive liner from the composition.