Objective: To provide scientific basis for the quality standard of Semen Descurainiae Tostum in 2010 edition of Pharmacopoeia. Method: The study of TLC identification and content determination was according to the appendix of 2005 edition of Pharmacopoeia. Result: In the 11 batches of the Semen Descurainiae Tostum

the content of quercetin-3-O-β-D-glucopyranosyl-7-O-β-D-gentiobioside was in the range of 0.076%~0.132%. The reference substance was well separated in the polyamide thin-layer chromatography and the solvent system consisted of acetoacetate-methanol-water(7 ∶2 ∶1). Conclution: The content limit of quercetin-3-O-β-D-glucopyranosyl-7-O-β-D-gentiobioside was set not less than 0.08%. The Stir-Frying did not affect the content of quercetin-3-O-β-D-glucopyranosyl-7-O-β-D-gentiobioside

the indicator substance. There was no distinction in reference substance content between Semen Descurainiae and Semen Descurainiae Tostum in TLC and HPLC.