Watson D.G., Oliveira E.J. (1999) Solid-phase extraction and gas chromatography-mass spectrometry determination of kaempferol and quercetin in human urine after consumption of Ginkgo biloba tablets. J Chromatogr B Biomed Sci Appl 723:203-10 PubMed (10080647)

Compound Mean content
Flavonoids, total 29.74 mg/tablet