17-Hydroxyjolkinolide A-B (1-2) and jolkinolide A-B (3-4) are four ent-13(15)-abietane-16,12-olide type diterpenoids isolated from the roots of Euphorbia fischeriana Steud. The absolute configurations of 1 and 2 were established by X-ray crystallographic analysis of their mono-bromobenzoate derivatives. On basis of our research, the absolute configuration of the butenolide of abietane can be determined by ECD spectra. The potential antituberculosis effects of these diterpenoids were evaluated using a Mycobacterium smegmatis model. The most potent compound according to the in vitro bioassay used was 17-hydroxyjolkinolide B (2) (MIC 1.8 mu g/mL).