I have a friend who was taking this regularly - anecdotally he had issues with blood clotting

Googling this comes back with

"The "memory enhancer" herb ginkgo biloba has been linked to bleeding problems. One of the components in this herb slows blood clotting. Consumers who take ginkgo with other medicines that prevent blood clots, such as Coumadin (warfarin) or aspirin, may increase their risk of bleeding."

https://www.consumermedsafety.org/safety-articles/be-cautious-with-ginkgo-biloba