In this study, we determined total polyphenol content(TPC) and total flavonoid content(TFC) of extracts from Korean cabbage and cabbage using a spectrophotometric method as well as glucosinolates concentration by HPLC. TPCs of Korean cabbage and cabbage extracts were 308.48 ㎍ GAE/g dry weight and 344.75 ㎍ GAE/g dry weight, respectively. TFCs of Korean cabbage and cabbage extracts were 5.33 ㎍ QE/g dry weight and 5.95 ㎍ QE/g dry weight, respectively. We found six different glucosinolates, namely progoitrin, glucoalyssin, gluconapin, glucobrassicanapin, glucobrassicin and 4- methoxyglucobrassicin in the Korean cabbage extract. In the cabbage extract, there was four glucosinolates, namely glucoraphanin, sinigrin, glucobrassicin and 4-methoxyglucobrassicin. We determined the cytotoxic effect of Korean cabbage and cabbage extracts in AGS human stomach cancer cells, HepG2 human hepatic cancer cells and LNCaP human prostate cancer cells by MTT assay. Dose-dependent relationships were found between the extract concentrations and cancer cell growth inhibition. The overall results support that both Korean cabbage and cabbage, the major vegetables in Korea, contain bioactive compounds such as polypheol, flavonoids as well as glucosinolates and they may play a positive role in cancer prevention.