Recent studies have shown that Ginkgo Biloba can be effective in reducing the severity of acute mountain sickness. In a double-blind, placebo-controlled study, 40 volunteers who lived at 1400m were taken rapidly to 4300m and spent the night. Compared to those taking the placebo, the subjects taking the ginkgo had half the incidence of AMS symptoms, and those who did become ill had far milder symptoms.

The protocol involved taking 120 mg of the ginkgo (or the placebo) twice daily for 5 days prior to the ascent, and continuing at altitude.

Maakestad K, Leadbetter G, Olson S, Hackett P. Ginko biloba reduces incidence and severity of acute mountain sickness.(Abstract) Proceedings Wilderness Medical Society Summer Conference, Park City, Utah. August 9-12, 2000.