Centaurea horrida has been used in folk medicine for many purposes as diuretic, antiinflammatory, hypotensive, antidiarrhetic, mild astringent, bitter tonic, stomachic, digestive, and emmenagogue and in cosmetics. An infusion of this plant is used to treat diabetes and digestive problems Also it is used as a wash for tired eyes and in conjunctivitis. C.horrida grown in Lebanon is widely used in the treatment of diarrhea, as antihypertensive and as hypoglycemic. Phytochemical investigation of the species grown in Lebanon led to the isolation and identification of five phenolic compounds isolated from methanol, ethyl acetate and butanol fractions of Centaurea extracts. Their structures were determined by NMR, MS, UV and IR methods. It is important to mention that the isolated flavonoids fisetin, hispidulin, quercetin, quercetin -3-D- galactoside and caffeic acid were isolated for the first time from Centaurea horrida. L growing in the Middle East.