Ginkgo biloba has been used medicinally for over 5000 years. Originally extracts were used to treat pulmonary diseases, such as bronchitis and asthma. More recently, however, ginkgo has been favored to prevent memory loss and dementia.  It is believed that flavonoids within the plant are responsible for its proposed medicinal effects, with over 40 different flavonoids have been isolated from leaves from the ginkgo tree.