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