The way of vegetable raw materials extraction which allows to receive nontoxical composition of biological active agents from poisonous plants such as Gratiola officinalis L. was described. The alkaloids exit changes with the increase of ethyl alcohol percentage (from 15% to 96%). The extract was obtained using 96% ethanol and did not give positive high quality reaction to the content of alkaloids. The chemical composition with new nontoxical biological active composition of Gratiola officinalis L. extract was investigated. The extract contains a previously unknown plant – bioflavonoid quercetin. The average value of quercetin in this extract using the calibration curve of the standard sample quercetin (98%) Sigma is 0.66%. In the dry rest of extractive substances (Gratiola officinalis L.) the quantity of quercetin was 350 mkg (obtained from 10 g of a dry grass) as was established by the method of a liquid chromatography. Introduction Now biologically active compositions of obtaining methods of raw medicinal plants (with the least side effects and with the maximum positive pharmacological action) are effectively investigated. Perennial plant of the family Scrophulariaceae – Gratiola officinalis L. is widespread in Eurasia and North America [1]. The plant is poisonous. Pets recognize and does not eat the Gratiola officinalis L. on the pastures, but this plant can get together with hay and cause poisoning; especially horses are sensitive to the Gratiola officinalis L. Quality of the Gratiola officinalis L. raw medicinal material is regulated by pharmacopoeial article 42‐2358‐85. Previously the Gratiola officinalis L. grass was а part of Zdrenko composition and was used as a symptomatic treatment of papillomatosis gastritis and as a laxative, anthelminthic, cardiotonic, diuretic and antiseptic remedy. The water infusions and 15% alcohol tincture of herb ware used [2]. The Gratiola officinalis L. grass extractions have a very high toxicity, so they are used together with mucous decoctions, for internal use with great caution and under compulsory medical supervision [3]. Different extraction methods from the same plant materials can result in a biologically active substance with different chemical composition and properties [4]. Thus the extractive substances remain toxic when receiving an extract from the raw materials Gratiola officinalis L. by extraction with 96% ethanol or methanol or isopropanol) and chloroform [5], in which chloroform fraction is produced and is used with non‐polar compounds, including toxic