The volatile constituents of twelve essential oils from Madagascar, namely those of Cinnamomum camphora (L.) Presl, Cinnamomum zeylanicum Blume (leaf oil), Hedychium flavum Roxb., Helichrysum gymnocephalum Humbert, Helichrysum selaginifolium L., Lantana camara L., Pelargonium roseum Willd., Piper nigrum L., Ravensara aromatica Havozo (bark oil and leaf oil), Vetiveria zizanioides (L.) Nash ex Small and Zingiber officinale Roscoe were identified and quantified by high resolution capillary gas chromatography coupled to mass spectrometry (HRGCâMS) and high resolution capillary gas chromatography (HRGC), respectively. In all the essential oils at least one of the five chiral monoterpenes citronellol, limonene, linalol, terpinen-4-ol and α-terpineol was detected. Analysis of the enantiomers using multidimensional capillary gas chromatography (MDGC) revealed specific enantiomeric excesses, except for linalol, which was found in racemic form in P. roseum essential oil. © 1997 John Wiley & Sons, Ltd.