Q. What is panax ginseng, what can it do for me, and how should I use it?

A. Panax ginseng, also known as Chinese, Asian or Korean ginseng, is an herb famous for its ability to help the body adapt to stress. In ancient China, the herb was so revered that at times, only the emperor was allowed to collect it. Panax ginseng has been used for thousands of years by doctors of Chinese medicine to boost physical and mental vitality in people of all ages. Modern research has confirmed that panax ginseng has remarkable abilities for improving physical performance, alleviating stress and preventing neurological diseases.

Panax ginseng has been taken by athletes throughout Asia to increase performance. A study published in the Journal of Sports Medicine and Physical Fitness found that panax ginseng can increase the body's capacity to cope with physical and mental stress by eliminating symptoms of fatigue. Another study, published in the International Journal of Sport Nutrition, found that ginseng improved psychomotor performance during exercise without affecting exercise capacity.

The primary active ingredients in panax ginseng are a class of compounds called ginsenosides. These compounds do not have a stimulating action, like caffeine, yet they are able to increase physical and mental efficiency.

An article in the journal Medical Hypotheses shines some light on why ginseng seems to help people cope with stress: It appears that ginseng affects enzymes responsible for how a person responds to stress. Some of these enzymes break down stress hormones into inactive compounds, while others affect the binding of stress hormones to cell receptors in the body.

Another remarkable quality of panax ginseng is that it may help prevent neurological diseases. A number of studies suggest that ginsenosides can protect nerve cells from free radical damage and inflammation, and may prevent the progression of conditions, such as Alzheimer's disease.

Panax ginseng can thin the blood, so it's best to avoid taking it while on blood-thinning medications. If you are diabetic, refrain from using panax ginseng with insulin, and monitor blood sugar closely if you are taking other diabetic drugs because ginseng can lower blood sugar. Avoid using the herb if you have hypertension, or if you are pregnant or lactating. Excessive intake could lead to headaches, palpitations, insomnia, water retention, or high blood pressure.

The recommended dose for panax ginseng is 100 milligrams (containing 7 percent ginsenosides) taken two to three times daily.

Laurie Steelsmith is a naturopathic physician, licensed acupuncturist and author of the book, "Natural Choices for Women's Health." You can reach her and read her past columns at www.drsteelsmith .com. This column is for information only. Consult your health provider for medical advice.