Disclosed herein is a method of manufacturing a bioadhesive film comprising, as a film-forming agent, an alginate salt of monovalent cation or a mixture of alginate salts of monovalent cation, the film-forming agent having a mean guluronate (G) content of from 50 to 85% by weight, a mean mannuronate (M) content of from 15 to 50% by weight, a mean molecular weight of from 30,000 g/mol to 90,000 g/mol and being such that a 10% aqueous solution thereof at a temperature of 20°C has a viscosity of 100-1000 mPas, as measured at a shear rate of 20 rpm by use of a Brookfield viscometer with a spindle No.2, by dissolving the film-forming agent in a solvent or mixture of solvents so as to obtain a liquid composition, distributing the composition onto a solid surface, and permitting the composition to dry on the surface, wherein said method does not include a melting step.