Treatment with ergolide, a sesquiterpene lactone from Inula britannica var chinensis, caused the induction of apoptosis in Jurkat T cells, which was confirmed by DNA fragmentation, caspase-3 activation and cleavage of poly(ADP-ribose) polymerase in response to ergolide. Furthermore, mitochondrial dysfunction appeared to be associated with ergolide-induced apoptosis, because Bax translocation and cytochrome c release were stimulated by ergolide. In parallel, the nuclear factor-kappaB (NF-kappaB) signaling pathway was significantly inhibited by ergolide, which was accompanied by down-regulation of cell survival molecules, such as X-chromosome-linked inhibitor of apoptosis and Bcl-2. In addition, the JNK signaling pathway was involved in ergolide-induced apoptosis. Collectively, our results identified a new mechanism for the anti-cancer property of ergolide, attributable to the induction of apoptosis through down-regulation of cell survival signal molecules resulting from inhibition of the NF-kappaB signaling pathway.