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Ginseng has been used for more than two millennia in China, where the earliest written description of its use appeared in a medical book written during the Han dynasty, before a.d. 100. At that time, the expert recommended it for “repairing the five viscera, quietening the spirit, curbing the emotion, stopping agitation, removing noxious influence, brightening the eyes, enlightening the mind, and increasing the wisdom.”

It has been a favorite tonic in China ever since then. In 1714, Père Jartoux, a Jesuit missionary who had spent time in Beijing, predicted that “any European who understands pharmacy” would be able to study its chemistry and adapt it as an excellent medicine.

Although the chemistry has been studied, the pharmacology is complicated and elusive. European science still has not been able to explain why the Chinese treasure it so much. Much of the research seems to yield contradictory results. Traditional Chinese medicine uses a completely different theoretical system. There ginseng is understood as a yang tonic that can increase strength, promote life and appetite, and overcome general debility, blocked qi (pronounced chee), and impotence.

There are several species of ginseng as well as different preparations that strongly influence the quality of the herb. American ginseng (Panax quinquefolius) is prized in Asia because it is sweeter tasting (rather than sweet-bitter like Panax ginseng) and is considered more yin (cooler) in nature. Panax notoginseng, or sanchi ginseng, is a dwarf variety that is sometimes substituted.

Regardless of species, the part of the plant used is the root. It should be collected in autumn from a plant five or six years old. Ginseng root may be fresh (preferably at least six years old), “white” ginseng root prepared by simple drying, or red ginseng root prepared by steaming first prior to drying. Processing methods alter the composition of the final product.

With ginseng drawing prices as high as $500 per wild-crafted root, it is little wonder that adulteration is a concern. Ginseng has become increasingly popular in the United States, with six million people taking it, but some ginseng products on the American market contain very little verifiable ginseng activity.

The American Botanical Council has undertaken a study of many proprietary products and found significant differences among them.

Active Ingredients

Ginseng is full of saponins termed ginsenosides. Approximately thirty of these compounds have been identified, and they appear to be responsible for most of the activity of ginseng. Their chemical structures are similar to those of steroids such as testosterone and estrogen. The picture is complex, however. Not only do the various species and forms of ginseng have different ginsenoside profiles, the ginsenosides themselves have differing and sometimes opposing actions. Ginsenoside Rb1, for example, seems to lead to sedation and lower blood pressure, while ginsenoside Rg1 acts as a stimulant and raises blood pressure.

These distinct pharmacological activities and the variation in composition from one piece of ginseng root to another, depending on variety, growing conditions, and processing, probably explain why research results on ginseng are inconsistent. Some commercial products are standardized to 4 percent ginsenosides and others to 7 percent.

Other ingredients of ginseng root may also have important activity. They include essential oil, phytosterol, carbohydrates, amino acids, peptides, vitamins, minerals, and some other ingredients. Nonsaponin constituents appear to be responsible for the ability of Korean red ginseng root to lower blood sugar in diabetics. Still other compounds may be responsible for ginseng’s apparent ability to stimulate nitric oxide formation, which may explain certain other of its traditional actions, including its reputed ability to help combat impotence.


The most common use of ginseng in Chinese medicine was (and perhaps still is) as a general tonic, and scientists have devoted a certain amount of effort to studying ginseng as an “adaptogen.” This category, which doesn’t correspond to any widely used pharmaceuticals, implies that ginseng is helpful in counteracting stress. Indeed, some researchers believe that the benefits of an adaptogen are apparent only when the organism has been stressed to its limits. Despite this, in a well-designed placebo-controlled study, ginseng ingestion for up to ninety-six days did not protect rats exposed to a highly stressful situation, having to swim in cold water.

In animals, ginseng is sedative at low doses and a stimulant at high doses. To some extent this is related to the effects of the different ginsenosides. Ginsenoside Rb1has a sedative effect and lowers blood pressure. It also has anticonvulsant and analgesic activity, lowers fever and has some anti-inflammatory action. Ginsenoside Rg1, on the other hand, is a stimulant and raises blood pressure at low doses, while at higher doses it has more sedative activity. At stimulant doses it can also aggravate ulcers and accelerates learning in animals.

Some studies of humans have shown that ginseng standardized extracts can help people react more quickly to both visual and auditory cues, increase concentration, and improve hand-eye coordination. Not all studies have reached similar conclusions. Ginseng can change body biochemistry, and a careful study of fifty male physical education teachers demonstrated that they were able to do significantly more work (defined in kilogram-meters) after ginseng administration than after placebo. Maximum oxygen uptake was higher. Holding workload constant, the teachers consumed less oxygen, produced less lactate in their muscles, and had lower heart rates when they had been given ginseng.

A number of other studies have also found that ginseng increased aerobic capacity, reduced lactate levels in the blood, and lowered heart rate during exercise. Many of these studies, however, did not include placebo controls. Animal studies demonstrate that ginseng extracts can have a protective effect when used to pretreat small mammals undergoing radiation.

Italian pharmacologists have found that pretreatment with a standard ginseng extract (G115) significantly improved immune response to vaccination against influenza compared to placebo pretreatment.

Some glycosides found in red ginseng appear to act as antioxidants. This property might be the foundation for the anticancer effect seen in one study of mice exposed to cancer-causing chemicals. Those who were given extract of six-year-old red ginseng in their drinking water developed significantly fewer lung tumors after injection with benzo(a)pyrene, a strong carcinogen. Fresh four-year-old ginseng was not protective. An epidemiological study in Korea suggested that people who use ginseng regularly may be less likely to come down with cancer, but further studies are needed.

Ginseng is reported to lower cholesterol, presumably by accelerating its metabolism and removal from the body. Studies in chickens indicate that low-density lipoprotein (sometimes termed “bad cholesterol”) is especially affected.

Ginsenoside Rg2 can keep blood platelets from aggregating, and ginsenoside Ro prevents fibrinogen from being converted to fibrin, an important clotting factor.

At least one active ginseng component inhibits thromboxane and thus might contribute to an anticoagulant effect.

In animals, extracts of Korean red ginseng have helped to control diabetes. One double-blind Finnish study considered the effects of ginseng extract on newly diagnosed human diabetics (non-insulin-dependent). The investigators found that ginseng improved patients’ mood and increased their sense of well-being. People taking ginseng, but not those on placebo treatment, had lower fasting blood glucose and more normal glycosylated hemoglobin levels. Further studies in this field are needed.


Dose varies depending on the preparation used. A tea may be prepared from teaspoon of dried root (1.75 gm) taken once or, at most, twice daily. Studies have used doses of 100, 200, 250, or 500 mg of various extract preparations. If there are dosing instructions on the label, they should be followed. Traditionally, ginseng root is used for extended periods. Some authorities recommend three to four weeks; others specify up to three months. One standardized product, Ginsana, is the extract G115 that has been used in a number of studies.

Special Precautions

Although ginseng is considered appropriate for pregnant women and newborn babies in many Asian cultures, too little information is available to determine if it is safe.

Because of the research showing that ginseng can lower blood sugar, diabetics should carefully monitor blood sugar while taking ginseng.

Adverse Effects

Ginseng appears to be extremely safe. More than six million Americans take it, not to mention uncounted Chinese people over the centuries, and very few appear to have had any trouble. Insomnia has been a side effect in some of the placebo-controlled studies. In many studies no side effects are reported.

Other side effects are controversial. Too often, the identity and purity of the herbal product are not determined, or there may be confounding factors.

One death is attributed to a ginseng product contaminated with ma huang (ephedra). One survey found that people using large doses of ginseng for two years or more complained of diarrhea, sleeplessness, nervousness, high blood pressure, and skin problems, although they maintained that ginseng use made them more alert and better able to cope.

Many of them were also taking high doses of caffeine and other substances, so it is not possible to sort out whether any of these side effects are truly due to ginseng overdose. One brief report from Paris concerned a law student who developed a sore throat and took antibiotics for several days. Then, with final exams looming, he turned to ginseng as he would have in his native China. Within a week he had developed a serious skin reaction known as Stevens-Johnson syndrome and had to be hospitalized. Stevens-Johnson syndrome is sometimes lethal. Fortunately, he recovered completely within thirty days.

The doctors who treated him did not have the ginseng preparation analyzed, but they speculated that it might have been adulterated with a nonsteroidal anti-inflammatory drug that could have been responsible for the reaction. They did not consider the antibiotics a potential trigger, although Stevens-Johnson syndrome is a rare but established reaction to some antibiotics.

It is prudent to stop ginseng and seek medical attention if a rash or major skin redness develops while taking the herb. Other side effects that have cropped up in ginseng users are breast pain in one woman and vaginal bleeding in another woman seventy-two years of age.

Possible Interactions

Despite research suggesting that ginseng might reduce platelet aggregation, the only reported interaction with Coumadin resulted in a decreased INR (a measure of blood’s propensity to clot). This suggests that ginseng may counteract Coumadin’s benefit. People taking this or other anticoagulant medications such as aspirin, Plavix, or Ticlid should exercise caution or avoid taking ginseng. Please discuss your use of ginseng with your physician.

Another potential drug interaction involved a Spanish woman who was taking lithium and amitriptyline for depression. She discontinued these medications and immediately began taking ginseng instead. Within two weeks she suffered a manic episode and was hospitalized. Her physicians blamed the ginseng, but it may be difficult to determine whether an interaction with the antidepressants or their discontinuation contributed to the manic reaction.

Using ginseng together with the MAO inhibitor phenelzine (Nardil) has also resulted in mania. A potentially fatal interaction was reported in a man with severe kidney disease. Ten days after he began taking a ginseng preparation that also contained germanium, he was hospitalized with severe edema and high blood pressure. In the hospital, where he did not have access to his dietary supplements, his diuretic started working again. He lost twenty-five pounds of fluid, and his blood pressure dropped. But after discharge, he resumed taking supplements and once more wound up with fluid retention and hypertension.

The physicians from Vanderbilt and the Veterans Affairs Medical Center in Memphis where he was treated hypothesized that the germanium in the supplements damaged the already compromised kidney and interfered with the action of the furosemide (Lasix). There is no way to determine whether ginseng itself might have interacted with the man’s medications, furosemide and cyclosporine.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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