Abstract: The present invention relates to compositions and methods for the treatment of diseases or conditions characterised by excess thrombin generation or activity. In particular, the invention provides combination compositions comprising low molecular weight heparin (LMWH) and low molecular weight dermatan sulphate (LMWDS). Such compositions are well suited for the treatment of said diseases or conditions, and they exert an effect which is greater than sum of the effects of LMWH and LMWDS if dosed as single agents, i.e. the combination composition exerts a synergistic effect.