I. Introduction
The interactions between biomedical entities contain rich information, which is of significance to the biomedical research field. Drug-Drug Interaction (DDI) refers to the phenomenon that the effect of one drug is changed by another drug. The mining of the interactions between drugs can guide patients to take drugs correctly and avoid the Adverse Drug Reactions caused by taking two or more drugs at the same time. Protein-Protein Interactions (PPIs) can be used to design therapeutic drugs, help researchers to recognize protein complexes and discover disease mechanisms. Therefore, there is an urgent need to automatically extract relations (like DDIs, PPIs) from the massive biomedical literature.