The rhizomes of Ferula communis yielded three antibacterial sesquiterpenes, namely, the new daucane ester 14-(o-hydroxycinnamoyloxy)-dauc-4,8-diene (1), ferulenol (2) and ferchromone (3). Compound 1 exhibited significant activity against Gram-positive bacteria, while 3 was found to be less active. Compound 2, on the other hand, demonstrated potent activity against Mycobacterium organisms, and its corresponding C-4-acetoxy derivative 9 was found to retain the same activity as well. In addition, the rhizomes yielded a number of inactive compounds, including 2-nor-1,2-secoferulenol, elemicin, colladonin, feselol and compounds 4 and 5. Structural assignments were largely based on the spectral data, especially the 2D NMR COSY and HETCOR experiments. (C) 1998 John Wiley & Sons, Ltd.