A pharmaceutical composition for use as a medicament for the treatment of lesions of the respiratory system, preferably lung lesions, said composition comprising - a biocompatible polymer of the following general formula AaXxY in which: A represents a monomer, X represents a group R 1 COOR 2 or -R 9 (C=O)R 10, Y represents an O or N-sulphonate group and has one of the following formulae -R 3 OSO 3 R 4, -R 5 NSO 3 R 6, R 7 SO 3 R 8 in which: R 1, R 3, R 5 and R 9 independently represent an aliphatic hydrocarbon chain, optionally branched and/or unsaturated and which optionally contains one or more aromatic rings with the exception of benzylamine and benzylamine sulphonate, R 2, R 4, R 6 and R 8 independently represent a hydrogen atom or a cation, R 7 and R 10 independently represent a bond or an aliphatic hydrocarbon chain, optionally branched and/or unsaturated, a represents the number of monomers, x represents the rate of substitution of monomers A by groups X, y represents the rate of substitution of monomers A by groups Y, and - hyaluronic acid. - a biocompatible polymer of the following general formula AaXxY in which: A represents a monomer, X represents a group R 1 COOR 2 or -R 9 (C=O)R 10, Y represents an O or N-sulphonate group and has one of the following formulae -R 3 OSO 3 R 4, -R 5 NSO 3 R 6, R 7 SO 3 R 8 in which: R 1, R 3, R 5 and R 9 independently represent an aliphatic hydrocarbon chain, optionally branched and/or unsaturated and which optionally contains one or more aromatic rings with the exception of benzylamine and benzylamine sulphonate, R 2, R 4, R 6 and R 8 independently represent a hydrogen atom or a cation, R 7 and R 10 independently represent a bond or an aliphatic hydrocarbon chain, optionally branched and/or unsaturated, a represents the number of monomers, x represents the rate of substitution of monomers A by groups X, y represents the rate of substitution of monomers A by groups Y, and A represents a monomer, X represents a group R 1 COOR 2 or -R 9 (C=O)R 10, Y represents an O or N-sulphonate group and has one of the following formulae -R 3 OSO 3 R 4, -R 5 NSO 3 R 6, R 7 SO 3 R 8 in which: R 1, R 3, R 5 and R 9 independently represent an aliphatic hydrocarbon chain, optionally branched and/or unsaturated and which optionally contains one or more aromatic rings with the exception of benzylamine and benzylamine sulphonate, R 2, R 4, R 6 and R 8 independently represent a hydrogen atom or a cation, R 7 and R 10 independently represent a bond or an aliphatic hydrocarbon chain, optionally branched and/or unsaturated, a represents the number of monomers, x represents the rate of substitution of monomers A by groups X, y represents the rate of substitution of monomers A by groups Y, and R 1, R 3, R 5 and R 9 independently represent an aliphatic hydrocarbon chain, optionally branched and/or unsaturated and which optionally contains one or more aromatic rings with the exception of benzylamine and benzylamine sulphonate, R 2, R 4, R 6 and R 8 independently represent a hydrogen atom or a cation, R 7 and R 10 independently represent a bond or an aliphatic hydrocarbon chain, optionally branched and/or unsaturated, a represents the number of monomers, x represents the rate of substitution of monomers A by groups X, y represents the rate of substitution of monomers A by groups Y, and - hyaluronic acid.