Bioassay-guided fractionation of anti-emetic constituents of Alpinia katsumadai Hayata was performed. Nine compounds including one novel compound, (3R,5S)-trans-3,5-dihydroxy-1,7-diphenyl-1-heptene (9) were isolated from it. Among these compounds, four diarylheptanoids, one sesquiterpenoid and one flavonoid showed anti-emetic activity on copper sulfate induced-emesis in young chicks.