A series of scarce triterpenoid alcohols and ketones of the 14α-methyl-9,19-cyclocholestane type has been isolated from roots and aerial parts of Costus tonkinensis. 24-Methylpollinastanone identified by GC-mass spectrometry including deuterium labelling experiments was found as a natural product for the first time. In addition, α-amyrin, β-amyrin, several common phytosterols and some 7-oxosterols were identified.