Ginkgo biloba is a herbal supplement, used as an antioxidant. It improves blood supply to the brain, n assumes to improve the memory n enhance the thinking ability. But its not the alternative option in Parkinson, but yes there are studies which emphasize the benefits of ginkgo in dementia (Alzheimer). So seen the age of pt even with Parkinson it will be beneficial as an adjuvant. So you should not stop the first line treatment of Parkinson, n can give this ginkgo as a supplement.