Tanacetum pseudoachillea is a perennial herb belonging to the Asteraceae family. Structurally, it has been found to contain 8-pinene, camphene, myrcene, o- and p-cymenes, nerol and geraniol. Tanapsin was isolated from Tanacetum pseudoachille flower heads. On the basis of spectral characteristics and chemical changes, it was determined that thanapsin has the structure of 6-angeloyloxy-1,4-dihydroxyeudesm-11(13)-ene-8,12-olide . Phytochemical studies have shown that the sesquiterpene lactones isolated from the tops of mountain ash are tanaxin, tanasin, tanapsin, tachylin and tavulin . In addition, this plant contains flavonoids. It is known that extracts obtained from many species of Tanacetum pseudoachille have choleretic, antispasmodic, anti-inflammatory, anti-microbial and anti-viral, anti-protozoal, anthelmintic activities.