This study was conducted to investigate the chemical components of rusty root for seeking the cause of rust. Na, Fe contents were higher in various tissues of six-year-old rusty root than healthy root. Contents of total sugar in epidermis of rusty root was low but crude lignin and suborn contents were high. Crude lipid content increased with the rate of rusty symptoms in each part of root respectively. Pentadecanoic, stearic, oleic, lignoseric acid contents increased in cortex of tap root with the rate of rusty symptoms but decreased in pith. Total ginsenoside and crude saponin contents increased , in pith and cortex of tap root with the rate of rusty symptoms but decreased in lateral and fine root.