If herbs had a social structure similar to people, ginkgo (Ginkgo biloba) would be a celebrity. This ancient tree of Asian origin has recently received an inordinate amount of public attention, appearing regularly on television, radio, and in print. While ginkgo, according to some, is the oldest living tree species, dating from over 200 million years ago, its fame in the United States is fairly recent.

In October 1997, the Journal of the American Medical Association (JAMA) published a study conducted by a variety of medical doctors working in medical colleges and medical centers around the country. The authors concluded that Ginkgo biloba was “capable of stabilizing and, in a substantial number of cases, improving the cognitive performance and the social functioning of demented patients for six months to one year.” In other words, the allopathic medical establishment acknowledged, in one of their most prestigious journals, what Chinese and Western herbalists have known for centuries: Ginkgo biloba helps improve brain function.

The JAMA study pushed ginkgo into the limelight; a whole host of further studies have kept it there. In the past 18 months, scientists used an array of animals, including mice, rats, and young, healthy human males, to conduct an assortment of studies on ginkgo. Researchers looked at the plant’s effectiveness in such things as reducing tissue damage in spinal cord injuries, protecting against inner ear damage, assisting in the success of plastic surgery; improve learning, test taking, brain membrane fluidity, and cognitive function.

In the spring of 1998, the University of California at San Francisco published a study indicating that Ginkgo biloba may have yet another role: improving antidepressant-induced sexual dysfunction. This adds up to a lot of fame and high expectations for a single plant!

Botanical background: an ancient, modern tree

Also known as the Maidenhair Tree, Ginkgo biloba has been used as medicine by the Chinese for over 5,000 years. It is a hardy and handsome tree, thought to be resistant to disease and pollution, thus suitable for planting in urban parks and busy sidewalk gardens. In Asia, ginkgo trees have graced temple gardens for centuries. Walk the streets of New York City and you’ll see (and sometimes smell) ginkgo trees at every turn. A mature ginkgo will have a lovely, spreading fan-shaped leaf, and the tree can reach heights of up to 130 feet.

Medicinal use: seeds & leaves of health

The ginkgo seeds, used medicinally in Traditional Chinese Medicine, are considered a gourmet delicacy in Japan and China. A word of caution: the seeds are only edible after specialized processing—don’t try to harvest them on your own!

The leaves of the ginkgo tree are the source of the medicine with which most North Americans are familiar. Active constituents include flavone glycosides, bioflavones, and lactones. Ginkgo extract typically has a bitter taste, containing a “bitter principle,” not unlike that found in wormwood or blessed thistle.

In that 1997 JAMA study, which concluded that ginkgo was effective in the treatment of dementia, patients were treated with 120 mg/day of an extract of Ginkgo biloba. Since that time, several other studies have been conducted using 60-120 mg of ginkgo extract daily.

For the most part, researchers have consistently utilized ginkgo preparations which are standardized to contain 24 percent ginkgo flavone glycosides and 6 percent terpenoids (also known as ginkgolides).

Traditionally, ginkgo has been used in the elderly for age-related memory loss and diminished mental functioning. In this capacity, it works as an antioxidant and as a blood thinner. By thinning the blood, ginkgo assists in guaranteeing a good supply of blood to the tiny vessels of the brain.

Its antioxidative properties help reduce damage to brain cells. Since the brain is 60 percent fat, there is some speculation that age-related dementia and other cognitive diseases may, in part, be due to free-radical damage caused by lipid (fat) biochemical breakdown (lipid peroxidation).

In fact, according to the PDR for Herbal Medicines (1998), “the ginkgolide B component” has a powerful blocking effect on something called platelet-activating factor (PAF) through its displacement of, or “giving the walking papers” to PAF from receptor binding sites. In this way, ginkgo helps prevent arterial thrombosis, clotting (or clumping) of blood.

Related to this is ginkgo’s help with intermittent claudication, which, according to Stedman’s Medical Dictionary (1976), is a condition caused by reduced blood supply to leg muscles due to blood-clumping in a leg’s arteries, one which brings on “lameness and pain.”

Ginkgo also helps with 1) organic brain dysfunction 2) vertigo/dizziness (vascular origin) 3) tinnitus/ringing in the ears (vascular origin) 4) Raynaud’s disease 5) chronically cold feet.

In clinical practice, ginkgo is found to be helpful in the treatment of depression as well as memory loss and Alzheimer’s. In depression, ginkgo, combined with St. John’s wort, Siberian ginseng (Eleutherococcus senticosis), and B vitamins, can, in many patients, be as effective as the selective serotonin re-uptake inhibitors (e.g., Prozac and Zoloft).

Other brain-related symptoms—fatigue, moodiness, and anxiety—respond nicely to ginkgo, and It has been found to be helpful for the short-term treatment of cerebral symptoms which are commonly secondary to medication withdrawal.

A word about side effects

A word about side effects in is order with any medication, herbal or otherwise, that is both highly popular and overwhelmingly promising in the treatment of common complaints. As a potent blood thinner, ginkgo can be dangerous. Side effects such as subdural hematomas and bleeding in the eyes have been reported in a few isolated cases. Anyone taking a prescription blood thinner or antithrombotic medication, or, for that matter, aspirin, on a regular basis, should consult with a healthcare practitioner before taking ginkgo.

Nausea, diarrhea, leg pain, and dizziness can be caused by taking ginkgo extract. While rare, these side effects are significant and can, for some, occur with even low doses of ginkgo. Anyone who notices changes in their health or well-being shortly after taking ginkgo should discontinue using it.