revealed radiation sensitivities of root extracts and authentic compounds differed significantly. Both shikonin and deoxyshikonin were the most sensitive with a degradation rate of 87-91%, while other derivatives in the extracts were the most resistant with a rate of 44-67%. Mixture of shikonin and deoxyshikonin showed a degradation rate of 20-24% at 4 kGy and around 60% at 8 kGy, whereas other shikonin derivatives showed a 48- 62% degradation rate at 4 kGy and an 89-94% degradation at 8 kGy. The degradation pattern of shikonin derivatives in the mixture exhibited a similar pattern to those of the extract, but showed opposite pattern in individual derivative. The order of radiation sensitivity of shikonin derivatives are as follows: shikonin, deoxyshikonin>acetylshikonin, dimethylacrylshikonin, isobutyrylshikonin, isovalerylshikonin, 2-methyl-n-hutyrylshikonin>hydroxyisovalerylshikonin in authentic compounds and isobutyrylshikonin, acetylsbikonin, hydroxyisovalerylshikonin, isovalerylshikonin, 2-methyln-butyrylshikonin>deoxyshikonin, dimethylacrylshikonin>shikonin in root extracts.