In addition to trans-communol and trans-communic acid (obtained in the form of the methyl ester), seven new diterpenoids were isolated as non basic constituents from fresh bulbs of Fritillaria thunbergii MIQ. (Liliaceae). Their structures were determined to be isopimaran-19-ol (3), isopimaran-19-oic acid [obtained in the form of the methyl ester (4)], ent-kauran-16β, 17-diol (5), ent-kauran-16α, 17-diol (6), ent-16β, 17-epoxy-kaurane (7), ent-16α-methoxy-kauran-17-ol (8), and ent-kaur-15-en-17-ol (9).