This paper reports the circular dichroism and octant rule projection of 5 diterpenoids from Mallotus anomalus (compounds 1-5) and 3 sesquiterpenoids tussilagones (compounds 6-8): they are new compounds. Using ketone octant rule, planar cyclohexenone rule, beta, gamma-unsaturated ketone rule and Harada rule, the nature of A/B and B/C ring fusion was determined, thus, their absolute configurations were assigned.