Objective: To study the metabolism of combination adiminastration of main components of Gegen Qinlian decoction in rats. Method: The urine samples were collected 0-24 h after ig main components of Gegen Qinlian decoction

then the samples were purified through C18 solid-phase extration cartridge. The purified samples were analyzed by UPLC-Q-TOF-MS. Identification and structural elucidation of the metabolites were performed by comparing the changes in molecular masses

retention times and full scan metabolisms(MS) spectra with those of the parent drug

and the relative data of authentic reference. Result: Sixteen metabolism were identified as puerarin

daidzin

daidzein

dihydrodaidzein

puerarin 4'-O-β-sulfate

puerarin-7-O-glucuronide

baicalin-6-O-β-glucose-7-O-β-glucopyranuronoside

baicalin-6-O-β-glucopyranuronoside-7-O-β-glucopyranuro-noside

thalifendine

berberrubine

demethyleneberberine

jatrorrhizine

demethyleneberberine-glucuronide

jatrorrhizine-glucuronide

berberrubine-9-O-β-D-glucuronide

demethyleneberberine-2

3-O-β-D-glucuronide. Conclusion: Oxidative demethylenation and subsequent glucuronidation are the major metabolic pathways of combination adiminastration of main components of Gegen Qinlian decoction

some components were mainly excreted unmetabolized in the urine; because of lower bioavailability

first-pass effect in intestine of glycyrrhizic acid

and only a minor part eliminated by urine

the metabolisms of it were not detected.