Metabolomics is the study of small molecules or metabolites in an organism under different conditions. It aims to understand metabolic processes by examining changes in metabolite levels in response to stimuli. Applications of metabolomics include biomarker discovery for diseases, drug discovery by measuring drug effectiveness, environmental monitoring by measuring effects of pollutants, and personalized medicine by identifying unique metabolic pathways in patients. Metabolomics also contributes to cancer research, microbiome studies, neuroscience research, aging research, and systems biology.