the present invention relates to a method for inhibiting and / or preventing angiogenesis , the method comprising the step of administering a biocompatible composition , which is polymerizable to a hydrogel - forming material and which is based on a hydrophilic polymer , for inhibiting and / or preventing angiogenesis or endothelial cell proliferation , wherein the hydrophilic polymer is crosslinkable serum albumin or crosslinkable serum protein , in a subject in need of being treated . the invention furthermore relates to a method for inhibiting and / or preventing angiogenesis or endothelial cell proliferation in a subject in need thereof , comprising the step of administering a polymerized hydrogel - material , which has been obtained by polymerizing a serum - albumin - or serum - protein - based composition .