Ginkgo biloba dietary supplements often contain an extract made from the Ginkgo leaf. Consult a physician before taking Ginkgo Biloba leaf extract -- especially if you are taking prescription medications. Ginkgo biloba seeds are used in herbal remedies, but leaf extract contains more of the most potent, medicinally active chemicals. Flavonoids and terpenoids are two families of phytochemicals that are responsible for Ginkgos health benefits. The herbal extract is not used raw but is mixed with enough dried Ginkgo leaves to produce a standardized product with 24 percent flavanol glycosides and 6 percent terpene lactones. The standard Ginkgo biloba extract found most dietary supplements is called EGb761.

As we all know the terpenoid compounds in Ginkgo can relax blood vessels, decrease blood viscosity and interfere with platelets sticking together and causing clots. The net effect is improved blood flow. Terpenoids make Ginkgo extract a natural treatment option to help prevent clot and plaque formation in coronary and peripheral blood vessels. Additionally, it can ease Raynauds syndrome and relieve pain in the legs caused by poor blood circulation. Blood flow is improved in the brain and small vessels in the eye as well.

While Flavonoid compounds in Ginkgo biloba extract are antioxidants and block cellular damage caused by free radicals. Decreasing free radical activity is said to help reduce the effects of aging, protect blood vessel walls, nerve cells and heart muscle. The combination of antioxidant and vasodilator properties are believed to help patients suffering from dementia. A 2010 study published in the "Journal of the American Medical Association" contradicts this belief. This large, long-term study looked at the effect of 120 mg of EGb 761 or placebo given twice daily to over 3,000 subjects. The average subject was 79 years old and was monitored an average of 6.1 years. The researchers concluded that Ginkgo biloba did not slow cognitive degradation nor improve memory, language facility or psycho-motor speed.

Ginkgo biloba extract interacts with such a wide variety of medications that it is imperative that the supplement not be taken without consulting with a physician. Ginkgos effect on clotting may intensify if ibuprofen, aspirin or prescription anti-platelet drugs are taken. The same warning applies for the blood thinner warfarin. Ginkgo also interacts with alprozolam, buspirone, fluoxitine, St. Johns wart, diabetes medications, seizure medications and blood pressure medications. In addition, Ginkgo biloba extract interferes with the action of certain liver enzymes that are responsible for breaking down and helping eliminate a wide variety of prescription drugs.