Objective: To investigate effect of X-ray irradiation on the contents of triterpenoids and flavonoids in Glycyrrhizae Radix et Rhizoma for increasing the mutation rate of cultivated product of this herb

and lay a foundation for molecular breeding of Glycyrrhizae Radix et Rhizoma. Method: Different radiation doses of X-ray were used to irradiate the seeds of Glycyrrhizae Radix et Rhizoma

which were cultivated for one year.The contents of two triterpenoids and four flavonoids were assayed by HPLC.And nonparametric test were used to analyze the contents and yields of these six components. Result: The contents and yields of these six components in radiation samples were higher than that in blank group.The yields of triterpenoids and flavonoids showed an increasing-decreasing-increasing pattern with the increase of radiation dose.Compared with the blank group

the yields of six components in radiation group increased dramatically at the radiation dose of 5 Gy

and declined slightly at the radiation dose of 10 Gy

then increased again at the radiation dose of 20 Gy

and reached the peak at the radiation dose of 50 Gy. Conclusion: X-ray irradiation treatment can increase the biomass of Glycyrrhizae Radix et Rhizoma and improve the contents and yields of six active components

its mechanism may be associated with gene mutation

which changes the accumulation of metabolites.