How much Gingko Biloba can I safely take per day?

Adults (over 18 years old)
80 to 240 milligrams of a 50:1 standardized leaf extract taken daily by mouth in 2 to 3 divided doses has been used and studied (standardized to 24% to 25% ginkgo flavone glycosides and 6% terpine lactones). Other forms used include tea (bags usually contain 30 milligrams of extract), 3 to 6 milliliters of 40 milligrams per milliliter extract daily in three divided doses, and "fortified" foods. Ginkgo seeds are potentially toxic and should be avoided. The German ginkgo product Tebonin®, given through the veins (IV), was removed from the German market due to significant side effects.

Children (under 18 years old)
There is not enough scientific evidence to recommend use of ginkgo in children.
See: nlm.nih.gov/medlineplus/druginfo/natural/patient-ginkgo.html#Dosing