Five new sesquiterpenes, named merrillianone (1), cyclomerrillianolide (2), merrillianolide (3), 1α-hydroxy-3-deoxypseudoanisatin (4) and 7-O-acetylanislactone B (5), were isolated from the pericarps of Illicium merrillianum, a species indigenous to southwestern China and Burma. Their structures were elucidated based on spectroscopic and chemical data. The structure of 1 was confirmed by X-ray crystallographic analysis of its acetylated derivative 1a to consist of a novel cagelike acetal and hemiacetal structure. The NMR data for compounds 2 and 3, which could not be separated due to an equilibrium mixture of keto and hemiacetal forms, were unambiguously assigned, respectively.