Both plants and animals are living things made up of similar cells as well as organelles, and their essence of life is the same. However, plants face more environmental stress than animals and generate excessive reactive oxygen species (ROS), a group of small molecules that can harm proteins, necessitating distinctive metabolic processes. Secondary metabolites in plants are a group of chemical components that can eliminate ROS and can also exhibit medicinal properties; therefore, herbal medicines are often closely linked to the ecological significance of secondary metabolites. Why plants contain so many, not few, active medicinal ingredients is unknown. The root of Scutellaria baicalensis, a popular herbal medicine, is rich in various flavonoids with diverse structural features. Sodium hydrosulfite (Na.sub.2 S.sub.2 O.sub.4) can produce O.sup.- .sub.2 radicals and induce physical conditions under environmental stress. Using UHPLC-ESI-Q-TOF-MS/MS analysis, a total of 25 different compounds were identified in the roots of S. baicalensis between the Na.sub.2 S.sub.2 O.sub.4 groups and suitable conditions. Based on the results of the t-test (P0.05) performed for the groups and ions with values of VIP greater than or equal to 2, the most significantly different chemical markers with Na.sub.2 S.sub.2 O.sub.4 treatment were shikimic acid, citric acid, baicalin, wogonoside, baicalein, wogonin, 3,5,7,2,6-pentahydroxyflavanone, 5,2,6-trihydroxy-7,8-dimethoxy flavone, chrysin, eriodictyol, 5,8-dihydroxy-6,7 -dimethoxy flavone, skullcapflavone II, and 5,7-dihydroxy-6,8,2,3-tetrame thoxyflavone, and most of them were free flavonoids with many phenolic hydroxyl or methoxyl groups and characteristically high antioxidant activities. S. baicalensis roots modified their ability to eliminate ROS and maintained the equilibrium of ROS through the multitudinous biosynthesis and conversion of flavonoids, which is similar to the equilibrium established by an intricate buffer solution and perfectly explains the diversity and complexity of medicinal plant ingredients.