This article presents the results of the study of the plant Lepidium ruderale L. A method was developed for the complete extraction of polyphenolic substances from the plant, using the method of high-performance liquid chromatography flavonoids were identified and determined in the plant: kaempferol, quercetin; using mass spectrometry method, isovitexin belonging to the class C of flavonoids was identified; the chelating activity of the plant Lepidium ruderale L. was studied and it was revealed that the plant has a high biological activity; the content of organic acids was determined by capillary electrophoresis
