Abstract The extracts from individual specimens of Satureja thymbra L. and Thymbra spicata L. were analyzed in detail by GC and GC/MS. This study confirms the existence of thymol- and carvacrol-containing chemotypes of both species, which have been found to grow in rather small and compositionally segregated populations. With the exception of the thymol/carvacrol ratio, the volatile constituent compositions ofboth species were found to be very similar. In addition to the biosynthetically interrelated thymol, carvacrol, Î³-terpinene and p-cymene, the other major volatiles of both species were Î²-caryophyllene, caryophyllene oxide, thymohydroquinone and thymoquinone.