Archive for the 'Herbal Medicines' Category

Valerian, known as garden heliotrope and by several other common names, grows wild in damp places in Europe, Asia, and North America. It is also cultivated. The plant is a perennial growing to three to four feet with big white, pink, or lavender flower clusters comprised of many individual flowers. The root and rhizome of the plant have a very strong odor and have long attracted attention for their ability to combat anxiety. Powdered root products and tinctures and extracts have official status in drug compendia in many European countries and in Canada. In Germany, valerian is listed for treatment of restlessness and nervous disorders of sleep. Until recent years it had official status in the United States, but now it can be sold only as a dietary supplement.

Effects

The root and rhizome of valerian contain 0.1 to 0.3 percent of a volatile oil that gives these plant parts their characteristic disagreeable odor. Remarkably, the compounds responsible for the anxiety and sedative effect of valerian are still not known despite valerian’s long history of medicinal use. The special combination of chemicals present in the root may be key to physiological effects observed. Studies using brain nerve terminals have shown that an extract of valerian root stimulates the release of a neurotransmitter in the body called GAB A. The resulting increase in brain GABA concentrations is likely to be how the plant improves sleep patterns and acts as a mild tranquilizer.

The roots, rhizomes, and extracts of valerian clearly have mild sedative and antianxiety effects in both laboratory animals and humans. But mild is the operative word. Valerian can be taken without a serious adverse effect and without the addiction potential so characteristic of sedative and tranquilizer drugs.

Evidence of Efficacy

Several clinical studies have evaluated the effect of valerian on sleep, but these studies have limitations because they tested a small number of patients or healthy volunteers and were short duration. Nevertheless, the consensus from an evaluation of the better studies is that valerian is effective as a mild sedative.

For example, in 1982 investigators from Switzerland studied 128 volunteers who look either placebo, valerian extract (400 mg), or a proprietary sleep product containing both valerian and hops. Each product was taken in random order on nonconsecutive nights. Study subjects filled out questionnaires on their nightly sleep patterns. Valerian helped people fall asleep sooner, and people reported they slept better, especially those who had previous sleep problems. (One problem with the study is that placebo was odor-free while valerian capsules had the plant’s characteristic odor.) Other scientific studies are in general agreement with these findings. There is little evidence to support the use of valerian as a mild tranquilizer, but most sedatives have antianxiety effect when taken in low doses.

Dangers

Animal studies have suggested that there is a possibility of liver damage with high doses of valerian, but close examination of the studies shows that other compounds in the products being tested (skullcap, for example) may be the culprit. Humans have been using valerian for many centuries, and there are no reports of serious adverse effects. Liver damage was not even evident in overdose situations. Because valerian is a mild sedative, it makes sense to avoid alcoholic beverages or other drugs causing drowsiness when taking a valerian product. In addition, be careful operating machinery or an automobile while taking valerian during the day because of the potential for drowsiness. Taking valerian at night did not cause sedation or “daytime hangover” the next day. A benzodiazepine drug taken for comparison purposes did have a morning-after effect. Other occasionally reported side effects include headache, restlessness, nausea, and blurred vision.

Recommendations

Valerian has been used for a long time as a mild sedative and tranquilizer. Clinical studies support this use and indicate that occasional use is safe. We suggest, as with any medication for sleep and anxiety, that valerian be used only as a temporary measure to get past the problem. It is most important to deal with the underlying reason for anxiety or trouble sleeping and not rely on a drug to solve the problem.

For sleep, 400 mg of the powdered root before bedtime is appropriate. For use of the liquid forms or of the extracts, follow the directions on the manufacturer’s label. For anxiety, a lower dose taken two or three times a day could serve as a temporary measure, though we do not recommend self-medicating in this way. Because of the possibility that valerian may cause liver image in high doses, you should not use it if you have liver disease. Because the effects of valerian on the fetus have not been tested, it should be avoided during pregnancy and breast-feeding, and it should not be used in children. Avoid alcohol and other sedative drugs while taking it. On balance, valerian is an old and underutilized medication that is a safe and effective mild sedative.

St. John’s wort is Hypericum perforatum, a low perennial shrub that develops beautiful yellow flowers in the spring. In Europe it is also commonly called hypericum. The plant is abundant on the West Coast of the United States and in fact is used as an ornamental landscape plant.

St. John’s wort has long been used for medicinal purposes. The plant juice has been applied directly to wounds to speed healing, and teas made with the leaves and tops of the plant have been used to treat urinary and lung diseases and mental depression. Today most attention is directed toward evaluating effectiveness of St. John’s wort and extracts of this plant in treating depression.

Depression, other than that which is self-limiting and initiated by a tragic event, is a common and debilitating disorder. There are many conventional antidepressants your doctor can prescribe, including TCAs (tricyclic antidepressants), SSRIs (selective serotonin reuptake inhibitors), and MAOIs (monoamine oxidase inhibitors). These drugs are effective, but many patients don’t want to use them because of their side effects, which include weight gain, fatigue, headache, and low blood pressure. An effective herbal without frequent side effects would be a welcome addition for many doctors and patients. St. John’s wort may be that herbal, and extracts of the flowering tops of the plant are now widely used in European countries for this purpose. Sixty-six million doses of St. John’s wort extract were prescribed in Germany during 1994, and there St. John’s wort is recognized as being useful for psychological disturbances, depression, anxiety, and nervous states.

Effects

St. John’s wort contains a red compound called hypericin that is a very mild MAO inhibitor. It also contains a phenolic compound called hyperforin, flavonoids, a volatile oil, and many other compounds. Hypericin has been considered the component with the antidepressant effect, but a recent German study of depressed patients indicates that hyperforin may be very important as well. So the actual identity of the plant component(s) with antidepressant activity is uncertain. Early studies demonstrated inhibition of MAO in laboratory tests but this is now thought to occur at doses unobtainable in the human brain. Other studies point to an alteration of receptors for chemical messengers in the brain as the mechanism or an effect on GABA. More work needs to be done to pinpoint the way St. John’s wort works and what chemical or chemicals in the plant are important. As with most herbs, current thinking is that the benefit is due to a synergistic mixture of many chemicals that make up the plant or its extract.

Evidence of Efficacy

More than twenty European clinical trials evaluating St. John’s wort as a treatment for depression have been completed. The consensus is that St. John’s wort is significantly better than placebo and equal to available conventional drugs for depression. A published meta-analysis (a statistical technique for combining and evaluating the evidence from multiple trials) examined the thirteen trials comparing St. John’s wort against placebo and showed that 55 percent of people in the St. John’s wort group improved on depression measures, compared to 22 percent taking placebo. An evaluation of three trials comparing St. John’s wort to conventional antidepressants revealed a 63 percent improvement rate for St. John’s wort and a 58 percent rate for the other drugs, an unimportant difference. Side effects were reported in 19.8 percent of the St. John’s wort group and in 35.9 percent of the group taking other drugs. Thus while more studis are needed, one can conclude that St. John’s wort extracts are more effective than placebo for the treatment of depression and may be equally effective as the conventional drugs to which it has been compared, with fewer side effects.

St. John’s wort has also been evaluated for seasonal affective disorder, a depression common in the late fall and winter seasons when days are shorter in the Northern Hemisphere. A group of German patients with severe symptoms was treated with St. John’s wort plus bright light or dim light. Both groups improved equally, indicating an application of this herb for severe “winter blues.”

DANGERS

Information from various clinical trials indicate that St. John wort has a low incidence of side effects. Stomach and intestinal upset, allergic reactions, fatigue, and emotional upset were reported. Additionally, St. John’s wort has the potential of causing sun sensitivity, so a sunblock is recommended when people use this herb. Nevertheless, serious drug toxicity reactions have not been reported from these trials.

RECOMMENDATIONS

St. John’s wort extracts offer an attractive alternative to conventional antidepressant drugs. The herb seems to be effective for mild to moderate depression, with few adverse effects when used in normal doses. More research is needed to directly compare the effectiveness of St. John’s wort to our most effective synthetic drugs for depression, St. John’s wort extracts may be useful, but if depression is serious enough to require drug treatment, a licensed health care provider should monitor your condition.

The recommended dose of St. John’s wort is 300 mg of a standardized extract containing 0.3 percent hypericin taken three times a day. This is the dose used in the clinical trials that have shown antidepression effects. As is the case with many other herbal products, several months of treatment are needed to produce a noticeable improvement. There are many products available that are promoted as “mood elevators” that contain numerous herbs in addition to St. John’s wort. These should be avoided because the contributions of the other herbs are unknown and because the amount of St. John’s wort in the usual dose may be too low.

Saw palmetto, Serenoa repens, is the dwarf palm or fan palm found in the southeastern United Stales; it is now cultivated for its medicinal value. The berry from this small tree has long been of interest for urinary tract problems.

European investigators studying the berry found that an extract of lipids from the dried berry contained a number of interesting steroidlike compounds called sitosterols. Several compounds in the berry act as antiandrogens, and later investigations in Europe revealed that the extract has useful activity for benign prostatic hypertropy (BPH). BPH is a noncancerous enlargement of the prostate gland that causes annoying urinary difficulties, low bladder retention volume (necessitating frequent urination), frequent waking to urinate at night, “dribbling” after urination, and decreased size and force of the urine stream. The problem stems from the prostate tissue pinching the urethra as it traverses the gland. BPH is a problem very commonly experienced by men over fifty; almost 90 percent of males over eighty have significant BPH. With BPH it is important to rule out prostate cancer before making the diagnosis. Conventional treatment for BPH involves either surgery or use of a drug such as finasteride (Proscar), which blocks the conversion of testosterone to 5-a-dihydrotestosterone, a hormone that has the ability to increase the growth of prostate tissue. Finasteride affects only the converting enzyme, so testosterone levels do not decline; though impotence has been reported as an adverse effect, it is not that common. Saw palmetto apparently works in a similar manner.

Effects

Like finasteride, lipid extracts of dried saw palmetto berries inhibit the enzyme that converts testosterone to 5-a-dihydrotestosterone. Studies using prostate tissue indicate that saw palmetto also blocks the binding of dihydrotestosterone to the tissue and has anti-inflammatory activity that could decrease symptoms of BPH. There is no change in testosterone levels in men taking saw palmetto, so impotence is not a problem.

Evidence of Efficacy

Exacts of saw palmetto have been used for some time in Europe and are now receiving attention in the United States. Recent clinical trials conducted in Europe support the use of this plant for BPH. For example, a randomized, double-blind clinical trial conducted at eighty-seven different health centers in nine European countries involving over a thousand patients who received either extract of saw palmetto (Permixon, 320 mg per day) or finasteride (5 mg per day) showed a 38 percent reduction in symptoms in both groups six months into the study, as well as changes in a number of other measurements that indicate substantial improvement in BPH. This comparison of saw palmetto and finasteride showed them to be equally effective. With respect to adverse effects, both were also well tolerated, but a sexual function score was higher with saw palmetto compared to finasteride. Thus the saw palmetto extract worked as well as finasteride in treating BPH but was not perceived by the patients to adversely affect sexual function. This study agrees with most previously reported, smaller studies and supports the use of the extract of this plant as a first-line treatment for early BPH.

Dangers

The lipid extract of saw palmetto is very well tolerated. Headache and stomach and intestinal upset are possible but infrequent side effects.

Recommendations

Most well-designed and controlled studies of saw palmetto in BPH have used a product called Permixon. The results show therapeutic benefit. Other preparations of saw palmetto are available. If you wish to treat BPH with saw palmetto, choose a standardized extract that contains greater than 85 percent fatty acids and sterols and that contains 160 mg of dried extract per capsule; take 320 mg per day. Studies show it may take six months to experience the full benefit from saw palmetto treatment. Of course, a licensed health care provider should monitor your therapy and the progress of your condition.

There is great confusion about terminology for the medicinal herb ginseng, and it is important that you understand what you are purchasing.

Panax ginseng can be found growing (now cultivated) in China. Korea, and Russia. In the United States, Panax quinquefolium grows wild in the hardwood forests of the eastern half of the United States and Canada. It is in high demand and has been overharvested to the point of being an endangered plant. Now ginseng harvesting is tightly regulated. Cultivation of the plant is important, but growth is slow and the grower must wait five to six years before the roots are considered ready for market. These difficulties make ginseng expensive; wild ginseng is exorbitantly expensive. The plant is a perennial, reaching a height of two feel. The feature that probably attracted early human healers to ginseng is the root system of the plant. The long taproots often have the appearance of a human with body (main root) and two legs (side roots). Sometimes a third large taproot gives the appearance of a phallus, reminiscent of the male human form, and this appearance has led to ginseng’s mystique of being a virility enhancer.

To add to the confusion, numerous products are made from the roots. Red ginseng is Asian ginseng cured by steaming and drying. White ginseng is the unheated dried root. Various extracts of the root are also available, as well as root powders to be used for teas.

Effects

Ginseng has been used as a sort of panacea for thousands of years in the Orient, particularly in China, Korea, and Japan. There it is believed to counteract fatigue and stress, increase resistance to disease, increase physical (including sexual) stamina, and improve mental functioning, among other health benefits. It probably cannot do all of these things. But can it do some of these things? Probably yes, to some extent.

Ginseng has been called an adaptogen, meaning it helps the body adapt to stress and disease and, in the process, will help “normalize” body functions. Ginseng cannot cure disease, but it is said to strengthen the body to help prevent and fight disease. These concepts are foreign to Western medicine, and until recently health providers considered ginseng to be an expensive Asian placebo. The only way to determine ginseng’s properties is to subject it to the same kind of scientific evaluation as other drug substances.

The chemistry of ginseng is reasonably well understood. Ginsenosides, which have the most important physiological activity, are steroidlike molecules found in the roots. Good-quality roots contain 2 to 3 percent ginsenosides, and good-quality commercial standardized extracts contain at least 4 percent ginsenosides. Other compounds in the ginseng root that contribute to its activiities include coumarins, flavinoids, and polysaccharides.

Evidence of Efficacy

Animal studies have shown that ginseng can increase physical performance (treadmill time, for example), increase resistance to physical stress (cold temperatures), improve memory (in maze tests), enhance markers of immune function, and reduce the number and growth rate of some slow-growing tumors in mice. Ginsenosides can function as antioxidants and free-radical scavengers, decreasing heart tissue injury. They increase the release of nitric oxide, a mediator of blood vessel vasodilation, improving blood flow. These effects might explain ginseng’s alleged ability to alleviate impotence.

But not all of these studies are well conducted and controlled, and the results of animal and tissue studies are not easily translated to humans. Nevertheless, several recent studies in humans indicate promise for ginseng in man. Unfortunately, not all of the human studies are scientifically valid, many studied a small number of patients or volunteers, and the studies were of short duration. Interestingly, almost none of these clinical studies was carried out in the United States or Canada.

A study from Korea, where ginseng use is widespread, involved nearly two thousand hospitalized patients. The investigators found that among people with and without cancer, ginseng users were more likely to be cancer free (75 percent versus 62 percent). Ginseng extract or dried powder seemed to be more protective than the fresh root or tea. Unfortunately this study did not control for smoking and diet, factors known to influence cancer. Nevertheless, this finding and the findings of many animal studies are encouraging and justify further research on the role of ginseng in cancer prevention.

One possible mechanism for the anticancer effects of ginseng is its ability to improve immune function, as indicated by animal studies. In an interesting Italian study, 227 volunteers received either placebo or a standardized extract of ginseng (100 mg) for twelve weeks. All participants received an influenza vaccination four weeks into the study. After the flu shot, forty-two people in the placebo group had a cold or flu, compared to fifteen in the group taking ginseng. Influenza antibody levels and natural killer cell activities were higher in the ginseng group. Nine cases of minor side effects were reported by the 227 volunteers, eight (insomnia, nausea, stomach pain) in the ginseng group and one in the placebo group (insomnia).

Finnish researchers studied the effects of ginseng in thirty-six newly diagnosed non-insulin-dependent diabetics. Patients were treated for eight weeks with placebo or ginseng (100 mg or 200 mg per day). Ginseng treatment, especially at the higher dose, caused a significant improvement in measures of psychophysical performance, mood, sense of well-being, vigor and physical activity. Importantly, chemical measures of diabetes status (hemoglobin A1C and fasting blood glucose) improved. The authors of this small (only twelve patients per experimental group) but well-designed study concluded that ginseng may be useful in the management of diabetes.

Several studies have evaluated the effects of ginseng on mood and well-being. The results suggest an effect, but more work is needed. A twelve-week Mexican study compared the effects of of a multivitamin preparation to the same preparation with added ginseng extract on 625 urban-dwelling volunteers. Quality of life, as measured by an eleven-item questionnaire, improved almost twofold in the vitamin plus ginseng group compared to the vitamin alone.

There is very little objective information about the effect of ginseng on impotence. A Korean study of ninety men with erectile dysfunction showed a significant improvement in men who took ginseng, compared to those who took placebo, but the study was published in an obscure journal. Studies are badly needed to be able to better evaluate ginseng’s effect on this condition.

Another popular use of ginseng that is not well supported is for the improvement of athletic performance. Animal studies of ginseng are generally positive, but the results of the very few trolled human studies do not suggest any benefit. In general, studies of ginseng in athletic performance do not follow established scientific methods and cannot be considered valid.

Dangers
Ginseng, like many other herbal products, is remarkably safe. No serious side effects have been reported in the people participating in recent controlled clinical trials, although not all studies kept track of side effects. There have been a few reports of problems, but unreasonably high doses (6-10 times the usual doses) were being used in some cases or there was a question about the ginseng being tested. Sleeplessness, agitation, nervousness, diarrhea, swollen and tender breasts, postmenopausal vaginal bleeding, rashes, and blood pressure changes have been reported rarely. If your blood pressure is poorly controlled, avoid ginseng. Do not take it during pregnancy.

Recommendations

Ginseng has been used in China since antiquity. Later its popularity spread to other Asian countries, and now it is growing in North America, This fascinating plant contains a mixture of chemicals in its roots that certainly has some physiological effects when taken continuously for at least several months, but nothing has been proven conclusively. What evidence there is points to a subtle tonic effect that is poorly appreciated in Western medicine. Ginseng may increase your feeling of well-being and stimulate the immune system. The extent to which these effects can actually help you is unknown, as is the value of ginseng in male impotence and in improving athletic performance. A myriad of other proposed uses for ginseng are also unproven.

If you wish to take ginseng, we suggest using a standardized extract of Asian ginseng root. Most positive studies have been done using extracts standardized to 4 percent ginsenosides. Take 100 to 200 mg per day for at least two months to notice benefits.

Ginkgo biloba is a commonly cultivated tree in many countries. The trees are long-lived (up to a thousand years) and have been estimated to have been growing on this planet for nearly 200 million years. The Ginkgo Petrified Forest State Park in Washington State, near the Columbia River, contains exposed petrified logs of trees that were growing millions of years ago. The tree is adaptable to an urban climate and is a common street side tree in many large cities. Good examples are found near the White House and Washington Monument in Washington, D. C., and on the campus of the University of California. Berkeley. The fan-shaped leaves and the seeds from the fruit are mentioned in ancient Chinese pharmacopeias (drug compilations), and traditional Chinese medicine uses teas prepared from the leaves as remedies for asthma and bronchitis. Only since the 1950s, however, has a very valuable therapeutic property of the plant been discovered: its ability to improve blood circulation.

The development of ginkgo as a therapeutic agent is an excellent example of the value of a strong commercial interest in the product. A German firm developed an extract of the tree leaves that contained concentrations of compounds large enough to exert a beneficial effect on circulation. This company patented the extraction process and funded many of the better human studies to define the herbal’s therapeutic usefulness.

Effects

Ginkgo contains two types of compounds that contribute most of the beneficial effects on blood. One type, the bioflavonoids, was discussed briefly in conjunction with vitamin C. Bioflavonoids derived from citrus fruits have been used to improve capillary blood flow. There is some scientific evidence for this use, as these compounds seem to make capillaries less brittle at “leaky.” Flavonoids also are strong antioxidants and stop blood platelets from sticking together. Ginkgo leaves contain several fiavonoids of importance: quercetin, kaempferol, and isorhamnetin. Ginkgo fiavonoids are linked to sugars so they are called flavonoid glycosides. The commercial exacts that have been studied are standardized to contain 24 percent ginkgo flavonoid glycosides.

Terpenoids are the other important group of compounds in ginkgo. Terpenoids are very common in plants, but ginkgo has several unique diterpenes. Ginkgolide B blocks a platelet aggregating factor manufactured in the body. There is also evidence that the terpenoids may protect nerve cells and help in the nerve repair process as well as having a favorable effect on capillary circulation.

Evidence of Efficacy

The standardized extract from the leaves of Ginkgo biloba is the best studied herbal product available. There have been over forty clinical trials of ginkgo extract, and its effectiveness seems established for two conditions: poor blood flow to the brain (cerebrovascular insufficiency) and legs (peripheral circulatory problems). The signs of poor blood circulation in the brain include poor short-term memory, confusion, slow mental response times, dizziness, ringing in the ears, depression, mood swings, and anxiety. These signs are also often present in senile dementia and in early Alzheimer’s disease. The relatively common condition known as intermittent claudication is a result of poor peripheral circulation. Characteristically, a person with intermittent claudication is unable to walk very far before cramping and pain in leg muscles become unbearable. Insufficient blood supply means that the lack of oxygen delivered to muscles in the legs results in pain, fatigue, and possible further injury.

Animal studies have clearly demonstrated that ginkgo extract improves blood flow to the brain and is a powerful antioxidant. In human studies, intravenously administered extract increased circulation in patients with poor blood flow. Several studies in older patients have shown ginkgo extract treatment to improve various test scores measuring memory and learning abilities. The doses used were 120 to 240 mg per day. It took three to six months for demonstrable improvements.

Recent studies conducted in Germany and the United States suggested ginkgo provides some benefit in early Alzheimer’s disease and dementia. In the German study, 28 percent of people who took ginkgo responded, as compared with 10 percent who received placebo—a highly significant finding. In the U.S study, treatment with 120 mg of the ginkgo extract for one year resulted in an overall delay in progression of the disease compared to placebo. While the benefits were modest the treatment was well tolerated. Given that traditional medicines have little impact on the progression of Alzheimer’s disease, a modest improvement with ginkgo is exciting. More studies to see if higher doses and longer treatment with ginkgo will be even more beneficial are clearly needed. It would be also of interest to evaluate a combination treatment of ginkgo and vitamin E, since vitamin E is an excellent antioxidant shown to have some benefit in Alzheimer’s disease.

Treatment effects are easy to measure in people with intermittent claudication. You simply measure the distance patients can walk on a treadmill. Studies comparing ginkgo to placebo have shown ginkgo to have a significant benefit. A recent analysis of all published clinical studies concluded that ginkgo extract was useful for the treatment of peripheral artery disease. Doses of at least 120 mg of ginkgo per day for at least six months were tested. As with Alzheimer’s disease and senile dementia, standard drug treatment of intermittent claudication is not very satisfactory, and ginkgo could play a valuable role in treatment.

Questions that should be addressed in future clinical studies include:

• Will ginkgo treatment improve memory and mental function in younger, disease-free individuals?

• Can ginkgo treatment delay Alzheimer’s disease and senile dementia?

• What other circulatory diseases will respond to gin treatment?

• Will the combination of ginkgo and other conventional drugs be synergistic in treatment?

• How much should you take and when should you take it?

Dangers

The manufacturer of Ginkgo biloba extract claims that over seven thousand patients have taken its product under clinical study conditions without serious side effects. They list headache, gastrointestinal upset, and allergic reactions as possible side effects. Given the ability of some ginkgo components to inhibit platelet aggregation, one concern we have is the possibility that ginkgo treatment will result in hemorrhage. Indeed, there have been recent reports of hemorrhage with ginkgo use. Ginkgo was not absolutely established as the cause, but users must be aware of this uncommon but serious side effect. If you have a tendency to clot slowly, are taking a blood thinner such as Coumadin. or are taking aspirin or Ticlid to block platelet adhesion, it seems prudent to avoid ginkgo.

Recommendations

Ginkgo biloba extract is reported to be among the most prescribed medicines in France and Germany, and its use is growing rapidly in North America. This ancient tree seems to be useful in circulatory disorders, but the true value of ginkgo preparations will be evident only after more study.

It is important to remember that ginkgo leaves probably don’t contain enough of the active constituents to provide a therapeutic effect. All ginkgo studies showing benefit have tested a concentrated leaf extract. Commercially available extracts are usually a fifty-fold concentrate. If you want to lake ginkgo to improve circulation, you should use a standardized extract of Ginkgo biloba leaves. As discussed earlier, it is better to buy an established, brand-name product, preferably the products based on the original German patent. In the United States, the label of these products will say “original standardized Ginkgo biloba exact” and “made using a patented process.”

We believe that treatment with 120 mg to 240 mg of a standardized extract of Ginkgo biloba leaves containing 24% fiavonoid glycosides and 6% terponoids for poor blood flow to the brain and intermittent cIaudication may be worthwhile. Treatment must be continued for at least three months before benefit be noticed. Avoid taking other drugs that affect blood clotting while you are taking ginkgo.

One of the world’s important spices, ginger is and has been since antiquity, consumed in significant quantities by many millions of people and is obviously a very safe herb. It is found naturally in tropical Asia but is now cultivated widely; Jamaica and China are big ginger producers. The plant is two to three feet in height with beautiful orchidlike flowers. The rhizomes (rootlike stems that send roots below and stems above) of this plant are of culinary and medicinal interest. You can buy fresh ginger rhizome or dried, powdered ginger in any supermarket. Both have a characteristically pungent taste and odor used to flavor foods and beverages (ginger ale, for example).

Effects

In addition to its dietary uses, ginger has been known since ancient times as a digestive aid and as a way of relieving stomach gas and cramps. More recently, ginger has been used to prevent nausea and vomiting. The rhizomes contain a volatile oil that gives ginger its pungent odor, but the active compounds are thought to be the same as those responsible for the pungent taste, namely gingerol, shogaol, and chemically related compounds in the rhizome. These compounds have some interesting physiological activities under experimental conditions including the ability to inhibit platelet adhesion, decrease diarrhea, inhibit formation of stomach ulcers and intestinal tumors in laboratory animals, and block synthesis of prostaglandins. The latter are important mediators of inflammation and have many diverse activities in the body. The ability to reduce prostaglandin synthesis in the stomach and intestine might be the mechanism for ginger’s antinausea effect.

Evidence of Efficacy

The evidence is strongest for ginger’s antinausea effect, yet even here the literature is not in full agreement. Of five placebo-controlled trials studying ginger for motion sickness, three said it worked and two said it did not. One study tested ginger versus placebo on eighty new naval cadets at sea. Vomiting and cold sweats were reduced compared to placebo, but nausea and dizziness or fainting were not. Another study placed thirty-six volunteers in a machine that spun them around. Those taking ginger were able to stay in the machine longer (336 seconds) than those receiving dimenhydrinate (also known as a Dramamine) (216 seconds) or placebo (90 seconds). Yet another study done by a different group showed a significant antinausea effect for scopolamine (a prescription antinausea agent) but not for ginger compared to placebo.

There is also disagreement on ginger’s ability to reduce post-operative nausea and vomiting. Several studies show that taking ginger before anesthesia reduces the number of episodes of nausea, while other studies were not able to demonstrate such effect.

What can be concluded about ginger’s ability to prevent nausea? In weighing the evidence, the German commission that regulates herbals determined that ginger is effective for indigestion and motion sickness at a dose of 2 to 4 g per day. We agree. There are very few nonprescription options for nausea. While its effectiveness has not been conclusively proven, ginger is nontoxic and worth trying if you suffer from motion sickness and nausea. We hope this spice will be studied in larger well designed human studies.

One area of tremendous interest is whether ginger is safe and effective for nausea during the early stages of pregnancy. Currently there are no drugs approved for this purpose. One small study tested thirty pregnant women with particularly severe morning sickness. Patients received 250 mg of ginger or a placebo four times a day. About 70 percent preferred ginger to placebo and claimed some relief. One researcher has raised the question of ginger affecting testosterone binding in the fetus on the basis of ginger’s ability to inhibit thromboxane syntheses, but this is speculative, and more recently one research group has ported that ginger does not affect thromboxane production in humans. Nevertheless, there is great concern about any drug used during the early months of pregnancy because of unknown risks for birth defects. With ginger, there is neither evidence of anything to worry about nor any evidence to establish its safety during pregnancy. Ginger proponents claim that its widespread use in foods without apparent harm to the fetus proves that it is safe, but most tread more cautiously due to a lack of hard information.

Neither the German commission nor the United States Pharmacopeia recommend that ginger be used medicinally during pregnancy. We also believe, however, that unremitting nausea during pregnancy is not without risk for the unborn. The expectant mother may not be able to eat, inadequately nourishing the fetus. Vomiting may also make her dehydrated, stressed, and subject to electrolyte imbalances. If nausea is serious and pro¬longed, the tiny risk of a problem for the fetus caused by ginger is probably smaller than the real risks of prolonged nausea and vomiting.

Many other uses have been suggested for ginger, such as a digestive aid, cough expectorant, or antiulcer agent, but there is little evidence to support them.

Dangers

Ginger is considered nontoxic. Occasional allergic reactions have been noted from inhalation of the powder, and some people complain of heartburn.

Recommendations

Ginger is worth trying for the prevention and relief of motion sickness and nausea. Ginger may be worth a trial for severe and prolonged nausea and vomiting in early pregnancy, but no studies lave been done to prove its safety, so talk to your doctor before ¬taking anything.

Suggested doses for the prevention of nausea are 500 mg to 1 g of the dried powder taken thirty minutes to one hour before travel or surgical anesthesia. Repeat doses may be needed. For treatment of nausea, a total of 2 g of dried ginger per day in divided doses is appropriate.