Ginkgo-24™ is a standardized concentration of prime quality Ginkgo biloba leaves. The extraction yields 24% ginkgo flavone glycosides and 6% terpene lactones (the key constituents) from a 50 to 1 concentration. The Ginkgo biloba tree has survived for over 200 million years, virtually unchanged -- the earth's oldest living species of tree. Ginkgo biloba 24% is the subject of extensive scientific research, and is used worldwide as an herbal supplement.