Ginkgo biloba: profile of a “brain booster”

The most potentially significant side effect associated with ginkgo biloba is bleeding.
By John Russo/

VICUS.COM (14 April 2000) — Ginkgo has been called a brain booster by Lester Packer in his book, The Antioxidant Miracle. In Germany and France, ginkgo is often prescribed to treat people with difficulty concentrating, poor memory, confusion, depression or anxiety. Ginkgo may also have a  role in treating Alzheimer’s disease (Klepser, 1999).

Ginkgo is generally safe and well tolerated. Severe side effects are rare. The most commonly reported adverse effects include stomach upset, headache, dizziness, heart palpitations and vertigo (Klepser, 1999). A toxic syndrome known as “Gin-nan” food poisoning (tonic/clonic seizures and loss of consciousness) can occur after taking 50 ginkgo seeds (Guide to Popular Natural Products, 1999).

The most potentially significant side effect associated with ginkgo biloba is bleeding. Three cases have been reported in the medical literature (Klepser, 1999). Although it is not known for sure if the ginkgo was responsible, it is recommended that people avoid combining ginkgo biloba with aspirin or anticoagulant medications such as warfarin (Coumadin; Rosenblatt, 1997).

If ginkgo biloba is taken, it is important to remember some people may not tolerate ginkgo even in small doses.

Recommendations for ginkgo consumption include:

  • Do not use ginkgo if you have a blood-clotting disorder, or if you are pregnant or nursing.
  • Do not combine ginkgo biloba with drugs that may predispose you to bleeding, such as aspirin or warfarin (Coumadin).
  • Do not give ginkgo to children without a doctor’s supervision.
  • Use in medicinal amounts only in consultation with a health-care professional.
  • Tell your surgeon and anesthesiologist if you have been taking ginkgo biloba.

Recommendations for dosing:

The recommended dosage may vary, depending on the reason for taking ginkgo (indication). For indications related to mental function, the German government’s Commission E gives a dosing range of 120-240 mg native dry extract daily, divided in two or three doses. A typical schedule is 40 mg three times a day, with meals.

Response to ginkgo may take four to six weeks (Guide to Popular Natural Products, 1999). As with many herbal preparations, it is essential to choose a quality product and to consult with an appropriate health-care provider, particularly if you take other medications or have other significant health conditions.

Standardized preparations of ginkgo biloba contain 5% to 7% terpene lactones and 22% to 27% ginkgo flavonone glycosides (Blumenthal, 2000).

John Russo, Jr., PharmD, is senior vice president of medical communications at He is a pharmacist and medical writer with more than 20 years of experience in medical education.


Blumenthal M, Goldberg A, Brinckmann J. Herbal Medicine: Expanded Commission E Monographs. Newton (MA): Integrative Medicine Communications; 2000.

Guide to Popular Natural Products. St. Louis (MO): Facts and Comparisons; 1999. 

Klepser TB, Klepser ME. Unsafe and potentially safe herbal therapies. American Journal of Health-System Pharmacy. 1999; 56(2):25-38.

McLeskey CH, Meyer T, Baisden CE, Gloyna DF, Roberson CR. The incidence of herbal and selected nutraceutical use in surgical patients (abstract). American Society of Anesthesiologists; 1999.

Packer L, Colman C. The Antioxidant Miracle. New York (NY): John Wiley and Sons, Inc.; 1999.

Rosenblatt M, Mindel J. Spontaneous hyphema associated with ingestion of Ginkgo biloba extract. New England Journal of Medicine. 1997; 336(15):1108.