Overview of the Ontology-Driven Hypothetic Assertion (OHA) framework. Drug Interaction Ontology (DIO) provides triple views for events and pathways, namely, intension, extension, and attribute. White triangles in extension are molecular events such as CYP3A4 mediated metabolism of irinotecan. White rectangles and circles in attribute are molecules and organs respectively; the organs indicate the location of molecules. The gray triangles and arrowed dashed lines represent the hypothetic assertions generated by the OHA framework. The Pathway Object Constructor (POC) generates pathways by connecting molecular events. The Drug Interaction Detector (DID) detects drug interactions from the generated pathways and asserts the interactions as hypothetic assertions into DIO.