Viscous, optionally buffered, aqueous or aqueous alcoholic liquid compositions (A), for preparing the films of soft capsules to contain oily and/or aqueous solutions, are gelled immediately before use solely by thickeners (I) which gel instantaneously on contact with complexing solutions. Viscous, optionally buffered, aqueous or aqueous alcoholic liquid compositions (A), for preparing the films of soft capsules to contain oily and/or aqueous solutions, are gelled immediately before use solely by thickeners (I) which gel instantaneously on contact with complexing solutions. (A) optionally also contain (i) a plasticizer (to control the elasticity of the films), (ii) a surfactant or polysaccharide (to control the disintegration of the films) and/or (iii) preservatives. An Independent claim is included for a method for preparing films from (A), involving: (1) forming a pseudo-colloidal solution of (I), in the cold or at not more than 70degreesC, by dispersing (I) (optionally together with other thickeners) in an optionally buffered aqueous or aqueous alcoholic solution containing alkali(ne earth) metal ions, a plasticizer, a surfactant and/or a disintegrating agent (2) storing the solution at 25-30degreesC (3) forming films for soft capsules at 25-30degreesC and (4) gelling the films by applying a complexing solution by spraying and/or dipping, either simultaneously on both faces of the film or alternately after removal of the film from its support.