The name "ginseng" is used to refer to both American (Panax quinquefolius) and Asian or Korean ginseng (Panax ginseng), which belong to the species Panax and have a somewhat similar chemical makeup. Siberian ginseng or Eleuthero (Eleutherococcus senticosus), on the other hand, is an entirely different plant with different effects. It is distantly related to ginseng, but it does not contain the same active ingredients. Both Asian and American ginseng contain ginsenosides, substances that are thought to give ginseng its medicinal properties.

Like American ginseng, Asian ginseng is a light tan, gnarled root that often looks like a human body with stringy shoots for arms and legs. Thousands of years ago, herbalists thought that because of the way ginseng looks it could treat many different kinds of ailments, from fatigue and stress to asthma and cancer. In traditional Chinese medicine, ginseng was often combined with other herbs and used often to bring longevity, strength, and wisdom to its users.

Ginseng is sometimes called an "adaptogen," an herb that helps the body deal with various kinds of stress, although there is no scientific evidence of adaptogens. But ginseng has been studied for several conditions, and it remains of the most popular herbs in the United States. Many of the studies examining Asian or Korean ginseng have used combinations of herbs, so it's not always possible to say whether ginseng alone had any benefit. Research on Asian ginseng has included the following:

Immune system health

Asian ginseng is believed to enhance the immune system, possibly helping the body fight off infection and disease. Several clinical studies report that Asian ginseng can improve immune function. Studies have found that ginseng seems to increase the number of immune cells in the blood, and improve the immune system's response to a flu vaccine. In one study, 227 participants received either ginseng or placebo for 12 weeks, with a flu shot administered after 4 weeks. The number of colds and flu were two-thirds lower in the group that took ginseng.

Cardiovascular health

Asian ginseng seems to have antioxidant effects, meaning it helps rid the body of free radicals, substances which can damage DNA and are thought to contribute to heart disease, diabetes, and other conditions. Preliminary studies suggest Asian ginseng may improve the symptoms of heart disease in humans. It also may decrease "bad" LDL cholesterol levels and raise "good" HDL cholesterol.

Its effect on blood pressure is more complicated. Some studies have found it seems to lower blood pressure, while others find it causes blood pressure to rise. That had led some people to theorize that ginseng may increase blood pressure at usual doses but lower it when doses are higher. Until researchers know for sure, you should not take ginseng if you have high blood pressure unless your doctor tells you it's OK.

Type 2 diabetes

Although American ginseng has been studied more for diabetes, both types of Panax ginsengs may lower blood sugar levels in those with type 2 diabetes. However, in a few studies it appeared that Asian or Korean ginseng worsened blood sugar levels. Some people think that the ginsenosides found in American ginseng might lower blood sugar while the different ginsenosides in Asian ginseng could raise blood sugar levels. Until more is known, you should not take ginseng if you have diabetes without your doctor's strict supervision and monitoring.

Mental performance

People who take ginseng often say they feel more alert. Several studies report that Asian ginseng may slightly improve thinking or learning. Early research shows that Asian ginseng may improve performance on such things as mental arithmetic, concentration, memory, and other measures. More research in this area, although not easy to do, would be helpful. Some studies have also found a positive effect with the combination use of Asian ginseng and Ginkgo biloba.

The studies have varied in what kinds of mental function they measured, making it hard to know exactly what the effects of ginseng are. For example, one study found an increase in the ability think abstractly among those who took ginseng, but no change in their reaction time or concentration levels.

Physical endurance

There have been a number of studies using Asian ginseng for athletic performance in humans and laboratory animals. Results have been mixed, with some studies showing increased strength and endurance, others showing improved agility or reaction time, and others showing no effect at all. Nevertheless, athletes often take Asian ginseng to boost both endurance and strength. Asian ginseng was also found to reduce fatigue in a study of 332 patients.

Stress andwell-being

Asian ginseng is sometimes called an "adaptogen," something that helps the body deal with stress, whether physical or mental. While that can be difficult to study, there is some evidence that ginseng (both Asian and American types) can improve quality of life -- although quality of life can be hard to measure, too. A study of 501 men and women living in Mexico City found significant improvements in quality of life measures (energy, sleep, sex life, personal satisfaction, well-being) in those taking Asian ginseng. Another well-designed study found that people taking a nutritional supplement with ginseng reported better quality of life than those taking the same supplement without ginseng.

Fertility/erectile dysfunction

Asian ginseng is widely believed to be capable of enhancing sexual performance, but there aren't many studies to back this up. In animal studies, Asian ginseng has increased sperm production, sexual activity, and sexual performance. A study of 46 men has also shown an increase in sperm count as well as motility. Another study in 60 men found that Asian ginseng increased libido (sex drive) and decreased erection problems.

Alzheimer's disease

Individual reports and animal studies indicate that Asian ginseng may slow the progression of Alzheimer's, decrease senility, and improve memory and behavior. Studies of large groups of people are needed.

Cancer

Several studies suggest that Asian ginseng may reduce the risk of some types of cancers. In one observational study, researchers followed 4,634 people for 5 years and found that those who took ginseng had lower risk of lung, liver, pancreatic, ovarian, and stomach cancer. However, the study could not rule out other factors being responsible for the lower risk of cancer (including eating habits). And it found that taking ginseng as few as 3 times a year led to a dramatic reduction in cancer risk, which is hard to believe.

A number of studies have found that Asian ginseng seems to inhibit the growth of tumors, although researchers aren't yet sure how it might work in humans. More research is needed.

Menopausal symptoms

There have been only a few studies examining ginseng for menopausal symptoms. Two well-designed studies evaluating red Korean (Asian) ginseng suggest it may relieve some of the symptoms of menopause, improving mood (particularly feelings of depression) and sense of well-being. The ginseng product was used in combination with a vitamin and mineral supplement. But another double-blind, placebo-controlled study of 384 women found no effect.

The ginseng plant has leaves that grow in a circle around a straight stem. Yellowish-green umbrella-shaped flowers grow in the center and produce red berries. Ginseng has a taproot that roughly resembles the human body, with 2 "arms" and 2 "legs." Wrinkles around the neck of the root tell how old the plant is. Ginseng is not ready for medicinal use until it has grown for about 6 years. Asian or Chinese and Korean ginseng are the same plants, but grown in different areas. American ginseng is a relative in the same species, native to North America.

Asian ginseng supplements are made from the ginseng root, and the long, thin offshoots, called root hairs. Both Asian or Korean and American ginseng contain ginsenosides, saponins that are ginseng's active ingredients. In addition to ginsenosides, Asian ginseng also contains glycans (panaxans), polysaccharide fraction DPG-3-2, peptides, maltol, B vitamins, flavonoids, and volatile oil.

White ginseng (dried, peeled) or red ginseng (unpeeled root, steamed before drying) is available in water, water-and-alcohol, or alcohol liquid extracts, and in powders or capsules. Asian ginseng root is also available for making decoctions (boiling the root in water)

Be sure to read the label carefully so that you are purchasing the type of ginseng that you want. If you are looking for Asian ginseng, make sure you buy Korean, red, or Panax ginseng. If you are looking for American ginseng, you should buy Panax quinquefolius. Eleuthero (Eleutherococcus senticosus), which is sometimes called Siberian ginseng, may also be found in health food stores or pharmacies. It does not have the same active ingredients as Asian or American ginseng.

Pediatric

Ginseng is not recommended for use in children because of its stimulant properties.

Adult

• Standardized extract: 200 mg, 1 - 3 times daily, standardized to contain 4 - 5% ginsenosides
• Fresh root: 1 - 2 g, once daily for up to 3 months
• Dried root: 1/2 - 2 g, chew and swallow once daily
• Tincture (1:5): 1 - 2 teaspoonfuls, 1 - 3 times daily
• Fluid extract (1:1): 1/4 - 1/2 teaspoonful, 1 - 3 times daily

In healthy people who wish to increase physical or mental performance, to prevent illness, or to improve resistance to stress, Asian ginseng should be taken in cycles. For example, take every day for 2 - 3 weeks, then stop for 2 weeks, then resume.

For help recovering from an illness, older people should take larger doses, such as 500 mg, 2 times daily for 3 months. Alternatively, they may take the same dosage (500 mg, 2 times daily) for 1 month, followed by a 2-month break. This can then be repeated if needed. Ask your health care provider for more information.

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, contain components that can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a health care provider qualified in the field of botanical medicine.

Asian ginseng may cause nervousness or sleeplessness, particularly if taken at high doses or when combined with caffeine. Other side effects are rare but may include:

• High blood pressure
• Insomnia
• Restlessness
• Anxiety
• Euphoria
• Diarrhea
• Vomiting
• Headache
• Nosebleed
• Breast pain
• Vaginal bleeding

To avoid hypoglycemia (low blood sugar), even in people without diabetes, take Asian ginseng with food.

People with hypertension (high blood pressure) should not take Asian ginseng products without the close supervision of their doctor. At the same time, people with low blood pressure, as well as those with an acute illness, should use caution when taking Asian ginseng.

People with bipolar disorder should not take ginseng, because it may increase the risk of mania.

Pregnant or breastfeeding women should not take Asian ginseng. Asian ginseng may cause vaginal bleeding.

Women who have a history of breast cancer should not take ginseng.

Stop taking Asian ginseng at least 7 days prior to surgery. Asian ginseng may act as a blood thinner, increasing the risk of bleeding during or after a procedure.

If you are currently being treated with any of the following medications, you should not use Asian ginseng without first talking to your health care provider:

ACE inhibitors (blood pressure medications) -- Asian ginseng may interact with angiotensin-converting enzyme (ACE) inhibitors. These medications include:

• Captopril (Capoten)
• Benazepril (Lotensin)
• Enalapril (Vasotec)
• Lisinopril (Prinivil, Zestril)
• Fosinopril (Monopril)
• Ramipril (Altace)
• Perindopril (Aceon)
• Quinapril (Accupril)
• Moexipril (Univasc)
• Trandolapril (Mavik)

Calcium channel blockers (heart and blood pressure medications) -- Asian ginseng may alter the effects of certain heart medications, including calcium channel blockers. These medications include:

• Amlodipine (Norvasc)
• Diltiazem (Cardizem)
• Nifedipine (Procardia)

Blood thinning medications (anticoagulants) -- Asian ginseng may decrease the effectiveness of the blood-thinning medication warfarin. In addition, ginseng may inhibit platelet activity. For this reason, it should probably not be used with aspirin.

Caffeine -- Ginseng may increase the stimulant effect of caffeine, possibly causing nervousness, sweating, insomnia, or irregular heartbeat.

Diabetes medications -- Ginseng may lower blood sugar levels, increasing the risk of hypoglycemia (low blood sugar).

Stimulants -- Ginseng may increase the stimulant effect and side effects of some medications take for attention deficit hyperactivity disorder, including amphetamine and dextroamphetamine (Adderall) and methylphenidate (Concerta, Ritalin).

MAOIs (monoamine oxidase inhibitors) -- Ginseng may increase the risk of mania when taken with MAOIs, a type of antidepressant. There have been reports of interaction between ginseng and phenelzine (Nardil) causing headaches, tremors, and mania.

• Isocarboxazid (Marplan)
• Phenelzine (Nardil)
• Tranylcypromine (Parnate)

Morphine -- Asian ginseng may block the painkilling effects of morphine.

Adams LL, Gatchel RJ. Complementary and alternative medicine: applications and implications for cognitive functioning in elderly populations. Alt Ther. 2000;7(2):52-61.

Anderson GD, Rosito G, Mohustsy MA, et al. Drug interaction potential of soy extract and Panax ginseng. J Clin Pharmacol. 2003;43(6):643-648.

Ang-Lee MK, Moss J, Yuan C-S. Herbal medicines and perioperative care. JAMA. 2001;286(2):208-216.

Biondo PD, Robbins SJ, Walsh JD, McCargar LJ, Harber VJ, Field CJ. A randomized controlled crossover trial of the effect of ginseng consumption on the immune response to moderate exercise in healthy sedentary men. Appl Physiol Nutr Metab. 2008 Oct;33(5):966-75.

Blumenthal M, Goldberg A, Brinckman J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, Mass: Integrative Medicine Communications; 2000:170-177.

Bucci LR. Selected herbals and human exercise performance. Am J Clin Nutr. 2000;72(2 Suppl):624S-636S.

Carai MAM, Agabio R, Bombardelli E, et al. Potential use of medicinal plants in the treatment of alcoholism. Fitoterapia. 2000;71:S38-S42.

Cardinal BJ, Engels HJ. Ginseng does not enhance psychological well-being in healthy, young adults: Results of a double-blind, placebo-controlled, randomized clinical trial. J Am Diet Assoc. 2001;101:655-660.

Chen CF, Chiou WF, Zhang JT. Comparison of the pharmacological effects of Panax ginseng and Panax quinquefolium. Acta Pharmacol Sin. 2008 Sep;29(9):1103-8.

Coleman CI, Hebert JH, Reddy P. The effects of Panax ginseng on quality of life. J Clin Pharm Ther. 2003;28(1):5-15.

Ernst E. The risk-benefit profile of commonly used herbal therapies: ginkgo, St. John's wort, ginseng, echinacea, saw palmetto, and kava. Ann Intern Med. 2002;136(1):42-53.

Fugh-Berman A. Herb-drug interactions. Lancet. 2000;355:134-138.

Gyllenhaal C, Merritt SL, Peterson SD, et al. Efficacy and safety of herbal stimulants and sedatives in sleep disorders. Sleep Med Rev. 2000;4(2):229-251.

Harkey MR, Henderson GL, Gershwin ME, et al. Variability in commercial ginseng products: an analysis of 25 preparations. Am J Clin Nutr. 2001;73:1101-1106.

Hartley DE, Elsabagh S, File SE. Gincosan (a combination of Ginkgo biloba and Panax ginseng): the effects on mood and cognition of 6 and 12 weeks' treatment in post-menopausal women. Nutr Neurosci. 2004;7(5-6):325-333.

Hartz AJ, Bentler S, Noyes R, et al. Randomized controlled trial of Siberian ginseng for chronic fatigue. Psychol Med. 2004;34(1):51-61.

Heck AM, DeWitt BA, Lukes AL. Potential interactions between alternative therapies and warfarin. Am J Health Syst Pharm. 2000;57(13):1221-1227.

Heo JH, Lee ST, Chu K, Oh MJ, Park HJ, Shim JY, Kim M. An open-label trial of Korean red ginseng as an adjuvant treatment for cognitive impairment in patients with Alzheimer's disease. Eur J Neurol. 2008 Aug;15(8):865-8.

Hong B, Ji YH, Hong JH, et al. A double-blind crossover study evaluating the efficacy of korean red ginseng in patients with erectile dysfunction: a preliminary report. J Urol. 2002;168(5):2070-2073.

Izzo AA, Ernst E. Interactions between herbal medicines and prescribed drugs: a systematic review. Drugs. 2001;61(15):2163-2175.

Jang DJ, Lee MS, Shin BC, Lee YC, Ernst E. Red ginseng for treating erectile dysfunction: a systematic review. Br J Clin Pharmacol. 2008 Oct;66(4):444-50.

Jiang X, Williams KM, Liauw WS, et al. Effect of St John's wort and ginseng on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects. Br J Clin Pharmacol.2004;57(5):592-599.

Kabalak AA, Soyal OB, Urfalioglu A, et al. Menometrorrhagia and tachyarrhythmia after using oral and topical ginseng. J Womens Health. (Larchmt ) 2004;13(7):830-833

Kim K, Kim HY. Korean red ginseng stimulates insulin release from isolated rat pancreatic islets. J Ethnopharmacol. 2008 Nov 20;120(2):190-5.

Kim YO, Kim HJ, Kim GS, Park HG, Lim SJ, Seong NS, et al. Panax ginseng Protects Against Global Ischemia Injury in Rat Hippocampus. J Med Food. 2009 Feb;12(1):71-6.

Lieberman HR. The effects of ginseng, ephedrine, and caffeine on cognitive performance, mood and energy. Nutr Rev. 2001;59(4):91-102.

Liu J, Burdette JE, Xu H, et al. Evaluation of estrogenic activity of plant extracts for the potential treatment of menopausal symptoms. J Agric Food Chem. 2001;49(5):2472-2479.

Mantle D, Lennard TWJ, Pickering AT. Therapeutic applications of medicinal plants in the treatment of breast cancer: a review of their pharmacology, efficacy and tolerability. Adverse Drug React Toxicol Rev. 2000;19(3):2223-240.

Mantle D, Pickering AT, Perry AK. Medicinal plant extracts for the treatment of dementia: a review of their pharmacology, efficacy, and tolerability. CNS Drugs. 2000;13:201-213.

Ohya T, Usui Y, Okamoto K, et al. Management for fistula-in-ano with Ginseng and Tang-kuei Ten Combination. Pediatr Int. 2004;46(1):72-76.

Park SE, Park C, Kim SH, Hossain MA, Kim MY, Chung HY, et al. Korean red ginseng extract induces apoptosis and decreases telomerase activity in human leukemia cells. J Ethnopharmacol. 2009 Jan 21;121(2):304-12.

Sinclaire S. Male infertility: nutritional and environmental considerations. Alt Med Rev. 2000;5(1):28-38.

Sung J, Han K-H, Zo J-H, et al. Effects of red ginseng upon vascular endothelial function in patients with essential hypertension. American Journal of Chinese Medicine. 2000;28(2):205-216.

Vaes LP, Chyka PA. Interactions of warfarin with garlic, ginger, ginkgo, or ginseng: nature of the evidence. Ann Pharmacother. 2000;34(12):1478-1482.

Wargovich MJ. Colon cancer chemoprevention with ginseng and other botanicals. J Korean Med Sci. 2001;16 Suppl:S81-S86.