Abstract: An ethanol extract of Chloranthus henryi (Chloranthaceae) was subjected to various chromatographic procedures including silica gel column chromatography, MCI column chromatography, Sephadex LH-20 column chromatography, and preparative HPLC. Five purified sesquiterpenes analyzed by spectroscopic analyses (MS, IR, NMR) and single crystal X-ray diffraction were elucidated as (1S,6S,8R)-8-ethoxychlomultin C (1a), (1R,6R,8S)-8-ethoxychlomultin C (1b), (+)-phaeocaulin D (2), atractylenolide Ⅰ (3), and 8-β-ethoxyasterolid (4). Compounds 1a and 1b were a new pair of sesquiterpene enantiomers and compounds 2-4 were isolated from this plant for the first time. Compounds 1a, 1b, 2 and 3 increased cell viability in H₂O₂-treated PC12 cells from (43.41±1.59)% to (61.71±7.56)%, (66.05±5.61)%, (74.34±3.32)% and (69.58±5.02)% at 10 μmol·L^-1, respectively.