BACKGROUND: Chartolepis intermedia Boiss. and Centaurea ruthenica Lam. are new medicinal plants containing pharmacologically active sesquiterpene lactones grossheimin and cynaropicrin. The article discusses the methods for the isolation of grossheimin and cynaropicrin and presents the results of studying the pharmacological activity of the isolated sesquiterpene lactones. AIM: The aim of this work was chemical, morphological, and anatomical study of Ch. intermedia Boiss. and C. ruthenica Lam., determination of pharmacological activity to substantiate the possibility of using these plants as medicinal raw materials. METHODS: The antitumor activity of grossheimin was studied in white outbred rats and mice in 12 strains of transplanted tumors. The antiparasitic activity of grossheimin and cynaropicrin was studied during replication of models of experimental opisthorchiasis on male golden hamsters (Mesocricetus auratus) of the SPF category. Experiments in vivo were carried out on pastoral dogs infested with various types of helminths. The hypolipidemic activity of grossheimin was studied in experimental rats with a single intragastric administration of ethanol, causing acute hyperlipidemia. The antimicrobial activity of cynarpicrin was determined in relation to test strains of Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis and Gram-negative strains of Escherichia coli and Pseudomonas aeruginosa by the method of diffusion in agar. RESULTS: Characteristic diagnostic features for Ch. intermedia Boiss. and C. ruthenica Lam. were revealed, which make it possible to diagnose and standardize the medicinal plants under study. Pharmacological studies have shown that grossheimin and cynaropicrin have antitumor, antiparasitic, hypolipidemic, and antimicrobial activity. Grossheimin significantly inhibits the growth of sarcoma 180, Pliss lymphosarcoma, and Ehrlich’s solid tumor. On the model of acute hyperlipidemia caused by the introduction of ethanol, grossheimin had a hypolipidemic effect, reducing the serum levels of triacylglycerides, total cholesterol, and low-density lipoprotein cholesterol. Under in vitro conditions, grossheimin and cynaropicrin exhibited anthelmintic action against Opisthorchis felineus worms, and under in vivo conditions, cynaropicrin was up to 100% effective against tapeworm infections (Taenia sp.). CONCLUSION: It was determined that the quantitative yield of sesquiterpene lactones is provided by extraction of plant raw materials with an ethanol: water (1:1) mixture under the action of ultrasound. Characteristic diagnostic features for C. intermedia Boiss. and C. ruthenica Lam. were revealed, which make it possible to diagnose and standardize the medicinal plants under study.