The results of the study of the content of biologically active substances in the grass of the common steamer are presented. A study of the quality and determination of qualitative and quantitative content of biologically active substances in the grass of steamed common grass. The qualitative content of saponins, flavonoids, tannins, organic acids, vitamins was studied and the quantitative content of saponins and flavonoids was established. A study was conducted to study the antioxidant activity of water-ethanol extract of steamed grass.