**Abstract**

Plants have evolved the capacity to create a wide range of chemicals during the process of their existence. In contrast to specialized metabolites that accumulate in a small number of plant species, flavonoids are broadly distributed across the plant kingdom. Therefore, a detailed analysis of flavonoid metabolism in genomics and metabolomics is an ideal way to investigate how plants have developed their unique metabolic pathways during the process of evolution. Among the analysis methods used for flavonoids, the coupling of liquid chromatography (LC) with ultraviolet (UV) and/or electrospray ionization (ESI) mass spectrometric detection has been demonstrated as a powerful tool for the identification and quantification of phenolics in plant extracts. This chapter mainly introduces of chemistry and metabolism of flavonoids and the application of liquid chromatography in the analysis of plant flavonoids.

**Keywords:** flavonoid metabolism, liquid chromatography, secondary metabolites, phenolics and phenylpropanoids, flavonoids
