Abstract A water distilled essential oil from aerial parts of Tanacetum macrophyllum (Waldst. et Kit.) Schultz.Bip. was analyzed both by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/M S). The major components were identified as Î²-eudesmol (21.4%) and cis-chrysanthenol (12%). Seventy five components were characterized representing 86.5% of the oil.