More than 6000 different flavonoids have been identified, and surely this number will increase. The different flavonoids have diverse biological functions, including protection against ultraviolet (UV) radiation and phytopathogens, signaling during nodulation, male fertility, auxin transport, as well as the coloration of flowers as a visual signal that attracts pollinators.Creative Proteomics provides a fast and effective reversed-phase high-performance liquid chromatography (HPLC) method for simultaneous quantification of flavonoids.