This monograph systematically delineates the cutting-edge advancements and clinical translational implications of metabolomics in modern medicine, encompassing its mechanistic and diagnostic applications in metabolic-endocrine disorders, malignancies (also with a focused analysis of gastrointestinal tumors), liver diseases, cardiovascular conditions, neuropsychiatric disorders, and immune-mediated illnesses. It further explores its utility in evaluating Traditional Chinese medicine efficacy, its synergistic integration with big data and artificial intelligence, and the trajectory of emerging technological innovations in the field. By addressing core methodological bottlenecks, data standardization imperatives, and reproducibility challenges, this work elucidates the irreplaceable role of metabolomics in advancing the precision medicine paradigm, distinct from genomics and proteomics, serving as a critical scholarly resource for researchers, clinicians, and graduate students.