In the last decades new molecules able to bind antithrombin have been identified. The strategies used in this search have been based mainly on the synthesis or chemical modification of existing drugs, or in the application of natural compounds with similar properties to those currently used. Examples for such compounds are lignins and flavonoids, highly sulfated small organic ligands that seem to have similar properties to heparins. Therefore, the discovery of novel or improved drugs for given diseases or special groups of patients, is a very slow and expensive process. Nevertheless, recent results demonstrate the discovery using Virtual Screening (VS) of a novel molecular scaffold, different to the previous ones based on heparin. vs Horacio Pérez-Sánchez, Virtual Screening for the Discovery of New Anticoagulants