Twenty nine 6,7-seco-ent-kaurane-type diterpenoids including 18 new ones, laxiflorolides C-T (1-18), along with 21 known ones were obtained from Isodon eriocalyx var. laxiflora. Laxiflorolides E-G (3-5) are the first identified naturally occurring 6,7-seco-ent-kauranoids that feature a 3,6-epoxy unit, and laxi-florolide M (11) is the first identified naturally occurring 6-nor-6,7-seco-ent-kauranoid. The absolute configurations of compounds 1, 3, 6, and 11 were determined by single-crystal X-ray diffraction analyses. The cytotoxic activity of the isolates was evaluated by an MTF assay. (C) 2014 Elsevier Ltd. All rights reserved.