Phytochemicals are bioactive compounds synthesized by plants that exhibit a wide spectrum of therapeutic properties. Plants exhibit anti-inflammatory, antioxidant, anticancer, and neuroprotective effects. Recent advancements in omics technologies have significantly enhanced the understanding of biosynthesis, regulation, and functional roles of these metabolites in human health. This chapter highlights the biological potential of key phytochemicals such as flavonoids, alkaloids, polyphenols, terpenoids, and other compounds and their relevance in the chronic diseases management and prevention. The integration of high-throughput skills such as transcriptomics, genomics, proteomics, and metabolomics offers a widespread view of phytochemical biosynthetic pathways and disease-associated molecular mechanisms. Furthermore, multi-omics approaches are important in identifying disease markers, signaling pathways, and transcriptional regulators in chronic conditions such as cancer, diabetes, cardiovascular, and neurodegenerative disorders. Despite these advances, challenges remain in data integration, interpretation, and functional validation. Future directions emphasize the use of single-cell omics, spatial profiling, and synthetic biology for precision modulation of phytochemical production and therapeutic targeting. This chapter covers the importance of integrated omics approaches with disease factor analysis, paving the way for novel phytopharmaceuticals and systems-level disease intervention strategies.