Three new diterpenoids, scutelaterins A-C, have been isolated from Scutellaria lateriflora and their structures established as (11S,13S,16S)-2 beta,6 alpha,19-triacetoxy-4 alpha,18;11,16;15,16-triepoxy-neo-clerod-14-ene (scutelaterin A), (11S,13S,16S)-6 alpha,19-diacetoxy-2 beta-(2'-methyl)butyryloxy-4 alpha,18;11,16;15,16-triepoxy-neo-clerod-14-ene (scutelaterin B) and (11S,13S,15R and S)-6 alpha,19-diacetoxy-2 beta-(2'-methyl)butyryloxy-4 alpha,18;11,16;15,16- triepoxy-neo-clerodan-15-ol (scutelaterin C) by chemical and spectroscopic means. In addition, the already known neo-clerodanes ajugapitin and scutecyprol A were also found in the same source. (C) 1998 Elsevier Science Ltd. All rights reserved.