abstract the aim of this work was to determine the polyphenol content and chemical composition of the essential oils of some moroccan herbs: myrtle (myrtus communis l.), rockrose (cistus ladanifer l.) and montpellier cistus (cistus monspeliensis l.). the polyphenols were analyzed and identified by hplc and the essential oils were chemically analyzed and identified by gc/ms. the principal components of myrtle leaves essential oil were 1,8-cineole (40.37%) and -pinene (21.82%). major oil components of myrtle berry essential oil included 1,8-cineole (46.48%) and -pinene (24.52%). the essential oil of rockrose was characterized by a high content of 1,8-cineole (19.27%) and viridiflorol (16.38%), while the predominant compounds in montpellier cistus essential oil were 1,8-cineole (9.17%), bornyl acetate (9.14%) and -pinene (5.84%). myrtle berry contains small amounts of myricetin derivates (myricetin-3-o-galactoside and myricetin-3-o-rhamnoside), although anthocyanins (malvidin-3-o-glucoside, petunidin-3-o-glucoside) are present in large amounts. in cistus ladanifer and cistus monspeliensis the predominant flavonoids were 3,7'-di-o-methyl-kaempferol and 3-o-methyl-kaempferol.