One new triterpene, cycloart-24β-methoxy-3β-ol (1), and seven known com pounds, were isolated from the whole herb of Euphorbia makinoi. Their structures were established by spectral methods, and their cytotoxic activities were evaluated against three different cell lines. Com pound 1 showed marginal cytotoxic activity against the three human cancer cell lines while 3 showed marginal cytotoxic activity against Hep 3B and HT-29 cells in vitro.