Four new ENT-clerodane diterpenoids were isolated from the whole plant of Scutellaria barbata D. Don. (Labiatae). Their structures were elucidated by chemical methods and spectral analyses. in vitro, the four new compounds showed significant cytotoxic activities against three human cancer lines (HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells), and gave IC50 values in the range 3.1-7.2 microM.