<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A role used to assert the relationship between a biological process and a drug or chemical that stimulates the process. The role implies the direct physical interaction of a chemical or drug with a target molecule or complex that results in the initiation of the process. The domain and range for this role are 'Biological Process' and 'Drug, Food, Chemical or Biomedical Material', respectively.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>