Disclosed is the use of a compound comprising a modified oligonucleotide consisting of 12 to 30 linked nucleosides, wherein the modified oligonucleotide has a nucleobase sequence complementary to miR-21 or a precursor thereof, for the manufacture of a medicament for treating, preventing, or diagnosing fibrosis in a subject. Further disclosed is the use of a compound comprising a modified oligonucleotide consisting of 12 to 30 linked nucleosides, wherein the nucleobase sequence of the modified oligonucleotide is complementary to miR-2 1 or a precursor thereof, for the manufacture of a medicament for treating a fibroproliferative disorder. Further disclosed is an in vitro method for diagnosing fibrosis comprising the steps of: a. measuring the expression of miR-2 1 in a sample from a patient supposed to suffer from fibrosis wherein an elevated level of miR-21 in comparison to a control sample indicates fibrosis or a predisposition thereof.
