How anyone can take ginger at anything more than 250mg is really beyond me. Either it's because it's a blood thinner, or it's because of some other effects it has, but it causes transient headaches (especially exertional headaches), dizziness, and I can feel my pulse pounding like a hammer against a concrete wall in my head if I take a single step, even if I don't have headache. It's like too much blood is going to my brain. Makes me scared that a blood vessel might pop in my brain.
Ginkgo Biloba in high dosages can do some of the same so it's curious whether it's serotonin modulation (which has a direct effect on blood vessels) or blood thinning which causes these experiences.
At least ginger does not give me anxiety like ginkgo biloba.