The present invention relates to the use of 5-HT2 receptor antagonists and in particular of 8-α-ergolines such as lisuride, terguride and the derivatives thereof as 5-HT2B and 5-HT2A receptor antagonists and antioxidants in preferably higher-dosed and preferably continuous use for the treatment, progression prophylaxis and general prophylaxis of organ fibroses and other pathological organ remodeling caused by mesenchymal proliferation