Chemical compositions and physiological activities of Platycodon grandiflorum roots grown for 4 and 24 years were investigated. Chemical compositions of P. grandiflorum roots grown for 24 years were moisture 82.7%, crude protein 1.6%, crude lipid 2.1% crude ash 0.7%. total sugar 6.0% total dietary fiber 2.3% crude saponin 3.4mg% and ascorbic acid 3.0 mg%. Contents of each components in 24 years old roots were higher than that in 4 years old roots and the most abundant mineral was potassium being 879.9mg/kg. Physiological activities of solvent extract from P. grandiflorum roots grown for 4 and 24 years were high in order of ethanol methanol and water extract. The electron-donating abilities and nitrite-scavenging effect of solvent extract of 24 years were high in order of ethanol methanol and water extract. The electron-donating abilities and nitrite-scavenging effect of solvent extract of 24 years old roots were higher than those of 4 years of old roots in the range of 10~40% respectively.