The most important nonspecific stress-protecting function of flavonoids is antioxidant, which is associated with blocking the spread of free radicals in cells. Moreover, the effectiveness of individual classes of flavonoids as antioxidants is different; in particular, substances can differ by three or more times. The accumulation of flavonoids by individual plants is exceptionally high in plasticity. To estimate the total potential antioxidant activity, we proposed an indicator – the antioxidant status of flavonoids, taking into account the qualitative and quantitative composition of the identified flavonoids. It has been shown that relatively close values of this indicator can be formed due to different quantitative ratios of flavonoids – either a relatively large number of low-efficiency flavonoids or a much smaller number of high-efficiency ones can accumulate in plants. It has been established that this is characteristic of various species of plants that live in a variety of conditions – from horse marshes to the steppe zone and salt marshes.