Abstract: The present invention relates to polymers comprising monomer units derived from captopril, and their use in the treatment or prevention of collagen deposition, fibrosis, scars, burns, or unwanted tissue formation. The present invention further relates to processes for the preparation of said polymers and to pharmaceutical compositions and medical products comprising the polymers. Also encompassed by the present invention are polymers comprising monomer units derived from other ACE inhibitors such as zofenopril, alacepril, rentiapril or pivalopril, or from vasopeptidase inhibitors such as fasidotrilat, omapatrilat or ilepatril.