Four new diarylheptanoids [(5R)-trans-1, 7-diphenyl-5-hydroxy-6-hepten-3-one (VIIa), (3S, 5S)-trans-1, 7-diphenyl-3, 5-dihydroxy-1-heptene (VIIIa), trans-1, 7-diphenyl-5-hydroxy-1-heptene (IX) and trans, trans-1, 7-diphenyl-5-hydroxy-4, 6-heptadien-3-one (Xa)] have been isolated from the seeds of Alpinia katsumadai HAYATA, together with trans, trans-farnesol (I), trans-cinnamaldehyde, three flavonoids [alpinetin (II), cardamomin (III) and pinocembrin (IV)], and two known diarylheptanoids [(3S, 5R)-3, 5-dihydroxy-1, 7-diphenylheptane (V) and trans, trans-1, 7-diphenyl-4, 6-heptadien-3-one (VI)], and their structures were determined on the basis of chemical and spectral evidence. This is the first time that trans-cinnamaldehyde, IV, V and VI have been isolated from these seeds.