Body fluid metabolomics is an important branch of metabolomics. It focuses on animal body fluids, evaluating the impact of endogenous stimuli (such as drugs or toxins) on the body by qualitatively and quantitatively analyzing changes in endogenous metabolites within biological systems. Human metabolism involves a series of complex biophysical and biochemical reactions. The volume, electrolyte concentration, osmotic pressure, and pH of intracellular and extracellular fluids continuously influence cellu......