Ginkgo biloba extract has been therapeutically used for several decades to increase peripheral and cerebral blood flow as well as for the treatment of dementia. The extract contains multiple compounds such as flavonoids and terpenoids that are thought to contribute to its neuroprotective and vasotropic effects. In this review, we summarize the experimental results on the mechanism of neuroprotection induced by standardized extract of Ginkgo biloba leaves (EGb 761) and its constituents. The effects described mostly in animals include those on cerebral blood flow, neurotransmitter systems, cellular redox state and nitric oxide level. Furthermore, we discuss the current status of clinical trials as well as undesired side effects of EGb 761.