GC-MS data on the volatile oil (CS-oil) of Chrysanthemum sibiricum herbs led to the identification of 2-methoxythioanisol, (+)-camphor, geraniol, citral, thymol, eugenol, ${eta}-caryophyllene$ oxide, ${eta}-caryophyllene$, ${eta}-eudesmol$, juniper camphor together with an unknown substance using the mass spectral library and literature data. CS-oil exhibited significant cytotoxicities on HL-60 $(IC_{50};12.5;{mu}g/ml)$ cell and mild on HepG-2 cell $(IC_{50};102.4;{mu}g/ml)$, though the antioxidant ability was found not to be potent $(IC_{50};97.2;{mu}g/ml)$. However, the component eugenol showed potent antioxidant ability but mild cytotoxicity. Methyleugenol with no phenolic OH showed less potent cytotoxic and antioxidative properties than eugenol suggesting that phenolic OH plays an important role for the cytotoxic and antioxidant abilities. The oil-pretreatment prevented lipid peroxidation induced by bromobenzene in the rat. Therefore, it was demonstrated that CS-oil could be a cytotoxic agent with antioxidant properties.