Leaves of the Ginkgo biloba L. have been identified as a source of bioactive compounds and their consumption may lead to the improvement of the brain function. During two vegetation periods, extracts of green and yellow leaves of Ginkgo biloba were analyzed for their chemical constituents and health properties. Samples were analyzed via HPLC and GC methods for the presence and content of phytochemicals. The antioxidant effect towards DPPH and ABTS radicals was studied. The antioxidant activity of samples was measured in Rancimat and Oxidograph tests along with the effectiveness of samples as inhibitors against cholinesterase. The content of individual phytochemicals was found to depend on the harvesting period and type of solvent used in the extraction process. Gingko yellow leaf extracts showed highest radical-scavenging activity as well as cholinesterase inhibition activity, and can be a valuable raw material to produce extracts possessing high cholinesterase inhibition activity.