Ligusticum chuanxiong (Umbelliferae) is a perennial herb that has been used for invigoration of blood in Korean traditional medicine. It is especially important in gynecological therapy of amenorrhea and dysmenorrhea. In this study, the essential oil of L. chuanxiong was obtained by steam distillation and its main components of L. chuanxiong, Z-ligustilide and butylidene phthalide, were isolated by silica gel column chromatography. We investigated the cytotoxic effects of the essential oil fraction of L. chuanxiong and its main components on MCF-7, HeLa and SK-Hep-1 cell lines by measuring the number of surviving cancer cells after treatment through direct cell counting and MTT analysis, and by examining the morphological changes under the microscope. The essential oil from the rhizomes of L. chuanxiong and its main components showed significant cytotoxic activities for all three tested cell lines. We also observed morphological changes of shrinking and blebbing in the membranes of the three cell lines, depending on the concentration of L. chaunxiong oil or its main components.