What is ginkgo biloba?

Ginkgo extract, from the leaves of the Ginkgo biloba tree, has been used for thousands of years in traditional Chinese medicine. It's available in many forms. These include ginkgo tea, dietary supplements, and liquid or powder extracts.

Ginkgo dietary supplements appear to be safe for most people when taken in moderate amounts. But raw or roasted ginkgo seeds and the unprocessed leaves can be toxic.

Experts don't know if ginkgo is safe if you are pregnant or breastfeeding. Check with your doctor before taking ginkgo.

Taking ginkgo may increase the risk of bleeding in people who already have bleeding problems. Ginkgo is not recommended for people who are taking medicines that thin the blood (anticoagulants), such as warfarin (Coumadin), aspirin, or other NSAIDs. This is because ginkgo may reduce the blood's ability to clot. The combined effect of ginkgo and these medicines may be harmful.

The U.S. Food and Drug Administration (FDA) does not regulate dietary supplements in the same way it regulates medicines. A dietary supplement can be sold with limited or no research on how well it works or on its safety.

Always tell your doctor if you are using a dietary supplement or if you are thinking about combining a dietary supplement with your conventional medical treatment. It may not be safe to forgo your conventional medical treatment and rely only on a dietary supplement.

When using dietary supplements, keep in mind the following:

• Like conventional medicines, dietary supplements may cause side effects, trigger allergic reactions, or interact with prescription and nonprescription medicines or other supplements you might be taking. A side effect or interaction with another medicine or supplement may make other health conditions worse.
• The way dietary supplements are manufactured may not be standardized. Because of this, how well they work or any side effects they cause may differ among brands or even within different lots of the same brand. The form of supplement that you buy in health food or grocery stores may not be the same as the form used in research.
• Other than for vitamins and minerals, the long-term effects of most dietary supplements are not known.

Some people take ginkgo to help with allergies, anxiety, dementia, or memory and concentration problems.

So far, there isn't clear proof from science that taking ginkgo helps with these or other health problems.