Ginkgo biloba related bleeding occurred when combined with warfarin or aspirin (acetylsalicylic acid). (8)
Use of ginkgo biloba extract has been associated with excessive bleeding in 20 cases including 8 cases of bleeding in the brain, 4 of the eye, and several occurring after surgery. In the 3 cases where it was reported, discontinuation of ginkgo reduced bleeding time by lab tests. About one-third of these patients were found to also be taking drugs that prevent clotting of the blood (anticoagulants [warfarin], antiplatelets [aspirin], nonsteroidal, anti-inflammatory drugs [ibuprofen]). A study of 12 healthy individuals taking 120mg of ginkgo extract for 3 months showed a slight antiplatelet effect. Yet, 2 other studies showed no significant antiplatelet/anticoagulation effect in 32 healthy individuals taking either 120 mg, 240 mg (2x the normal dose), or 480 mg ginkgo daily for 2-weeks or in 50 healthy individuals taking 240 mg of ginko for one week. (12)