Abstract The rhizomes and leaf oils of Acorus calamus L. were analysed by GC and GCâMS; 29 and 30 constituents were identified from the rhizome and leaf oils, respectively, comprising 99.7% of each of the oils βâAsarone (83.2%) and αâasarone (9.7%) were the major constituents in the rhizome oil, while βâasarone (85.6%) and linalool (4.7%) were the major constituents in the leaf oil. Copyright © 2002 John Wiley &amp; Sons, Ltd.