Procedures are described for isolating turmerones from Curcuma longa rhizomes and for chromatographically separating alpha- from beta-turmerone. Using a combination of spectroscopic techniques (especially high field H-1 NMR spectroscopy and chiroptical methods) these compounds are shown to be (1'R,6S)-2-methyl-6-(4-methylcyclohexa-2,4-dienyl)hept-2-en-4-one 2 (alpha-turmerone) and (1'R,6S)-2-methyl-6-(4-methylenecyclohex-2-enyl)hept-2-en-4-one 3 (beta-turmerone).