A process for treating fibroses including administering a therapeutically effective amount of a pharmaceutical composition which includes at least one biocompatible polymer of the following general formula (I): AaXxYy wherein: A represents a monomer selected from the group consisting of a sugar or —(O—CH2—CH2—CO)—, X represents a carboxyl group bonded to monomer A, Y represents a sulfate or sulfonate group bonded to monomer A a represents the number of monomers A such that the mass of the polymers of formula (I) is greater than approximately 5,000 da, x represents a substitution rate of the monomers A by the groups X, which is between approximately 20 and 150%, and y represents a substitution rate of the monomers A by the groups Y, which is between approximately 30 and 150%.
