The composition of the essential oils of the Hypericum perforatum L., Hypericum tetrapterum Fries and Hypericum olympicum L. is reported. GC-MS analyses showed α-pinene (21.0%) and 2-methyl-octane (12.6%) as the most abundant components of H. perforatum, whilst α-copaene (11.3%) and α-longipinene (9.7%) were the major constituents of H. tetrapterum; those of H. olympicum oil were germacrene D (16.0%) and (E)-caryophyllene (7.4%). Copyright © 2005 John Wiley & Sons, Ltd.