Abstract:Ludongnin, a new spirosecokaurene diterpenoid was isolated from Rabdosia rubescens (Hemsl.) Hara colleeted in Lushi, Henan. The structure was estab- lished from its spectral and chemical evidence. It is the first instance of an ent- kaurene type diterpenoid possessing a γ-lactonic ring in between C6-C19, while all the other known type diterpenoids isolated from Rabdosia species are not γ-lactonic ring in between C6--C19.