AbstractRenealmia alpinia Rott. (Maas) (Zingiberaceae) seeds contain 14% of a dark brown oleoresin which was investigated by a combination of chromatographic and spectrometric techniques. The volatiles (4.4% of the oleoresin) extracted from the oil by hydro‐distillation were mainly monoterpene hydrocarbons (β‐pinene 22.3%, limonene 18.4% and β‐phellandrene 38.0%). The oleoresin was further fractionated by column chromatography. β‐Carotene, nerolidol and manool were detected. The main constituent (45%) was unambiguously identified as 8(17),12 (E)‐labdadien‐15,16‐dial and details of its structure were provided by NMR spectroscopy. Three other unidentified labdane diterpenes were also found in low amounts.