Abstract: A spirosecokaurenoid, angustifolin (Ⅰ) was isolated from the leaves of Rabdosia angustifolia (Dunn) Hara (Labiatae) and its structure was established from spectral and chemical evidence. One known diterpenoid, isodonal (V) was also isolated together with β-sitosterol. (Ⅰ) and (Ⅴ) showed in vitro cytotoxicity and in vivo tumor inhibitory activities.