A comprehensive database covering about 22,498 genes, 25,469 proteins, 1956 pathways, 6704 diseases, 5615 diseases, and 52 organs integrated from databases including the BioCarta, KEGG, NCI-Nature curated, Reactome, CTD, PharmGKB, DrugBank, and HOMER. IPAD is the first comprehensive database that can be used to analyze, discover, and validate enrichment and interassociation between pathway, disease, drug and organ. The interassociations allow further identification of enriched pathways, diseases, drugs and organs. The ability to choose multiple quantitative parameters (p-value, AE, RE, and MJI) provides us with powerful statistics and computation to accurately calculate enrichment and interassociation. And the cross-linking of multiple data sources enables subsequent validation.