<jats:title>Abstract</jats:title><jats:p>Two new diterpenoid alkaloids, racemulosines A (<jats:bold>1</jats:bold>) and B (<jats:bold>2</jats:bold>), were isolated from the roots of <jats:italic>Aconitum racemulosum</jats:italic> <jats:sc>Franch</jats:sc>. The structures of the new alkaloids were elucidated by analysis of physical and spectroscopic data, and the structure of <jats:bold>1</jats:bold> was further confirmed by a single‐crystal X‐ray diffraction analysis. Furthermore, compound <jats:bold>1</jats:bold>, at 2.25⋅10<jats:sup>−4</jats:sup> mol/l, showed moderate activity against platelet aggregation induced by PAF (platelet‐activation factor).