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The use of plants as medicine predates even the existence of humans: great apes consumed specific medicinal plants when they are ill. In Eisenberg's 1990 study, herbal medicine was found to be used by 3% of the U.S. population in 1990. This widely invoked survey almost certainly underestimated the actual prevalence of use, as it was limited to English-speaking participants with telephones. There is certainly higher utilization of herbs by herbal medicine, ginkgo biloba, herbs, ginko biloba, beloba, garlic, st johns wort, wart
About one quarter of our pharmaceuticals originally were derived from plants, and only a tiny fraction of plants have been screened for medicinal compounds. Plant-derived products used regularly by primary care physicians include oral contraceptives (the progestin component is derived from Diascorea villosa, the Mexican yam); digoxin from foxglove ( Digitalis lanata); cephalosporins, derived from a marine fungus ( Cephalosporium acremonium); cromolyn sodium, a khellin derivative from the Ayurvedic herb Ammi visnaga ; and the statins, which are derived from the fungus Aspergillus terreus.
Recently there has been renewed interest from both large and small pharmaceutical companies in searching for novel molecules from plants.Many herbs lose their activity when purified. This may be because the wrong compound was identified (each species
Evening primrose oil, high in the essential fatty acids linoleic and gamma-linolenic acid, may be effective for mastalgia. A Welsh series of 414 patients with either cyclic or noncyclic mastalgia found that evening primrose oil, in a dose of 3g daily (containing
Several trials indicate that feverfew ( Tanacetum parthenium) may be effective in migraine prophylaxis. A small study tested feverfew with drawal in regular users. Seventeen patients who ate fever few leaves daily to prevent migraine were randomized to herbal medicine, ginkgo biloba, herbs, ginko biloba, beloba
In a larger, cross-over study, 72 migraine patients were given either one capsule of dried feverfew or placebo daily for 4 months, then received the other therapy for 4 more months. Patients receiving feverfew had fewer migraines, less severe attacks, and less
Feverfew can cause aphthous ulcers, oral edema, or loss of taste. Taking the herb in capsules reduces but does not eliminate these effects.
One double blind controlled study of 21 patients found that capsaicin cream applied topically reduced tenderness and pain of
Evening primrose oil may help rheumatoid arthritis patients to reduce their use of painkillers; one study found that 60% of
Another study that used an olive oil placebo found evening primrose oil equivalent to the placebo and neither very effective.
Of 45 patients treated with topical capsaicin or placebo for fibromyalgia, those receiving capsaicin reported less tenderness at their trig ger points. A significant increase in grip strength also was noted.
Topical capsaicin (.025%) also has been tested in a vehicle-controlled trial of 14 subjects with vulvar vestibulitis, the nine subjects who had completed the study at the time of its presentation experienced a 77% reduction of pain.
Topical capsaicin may be useful for diabetic neuropathy; one study of 252 patients with diabetic neuropathy found that 69.5% of patients treated with the capsaicin cream reported pain improvement to their physicians compared with 53.4% of those on
Garlic ( Allium sativum) may have beneficial cardiovascular effects. Alliums (which also include onions) lower blood lipid levels, and may have anticoagulant and antioxidant effects as well. A placebo-controlled trial with 88 participants found that garlic decreased
Another double blind study of 40 patients with hypercholesterolemia found that after 4 months, the group taking garlic had a 21% reduction in total cholesterol, compared with a 3% reduction in the control group. Triglycerides also decreased 24% in the
A meta-analysis of five trials that examined the effect of garlic on cholesterol found that the equivalent of one half to one clove of garlic lowered cholesterol about 9% in the groups of patients studied. The rise in blood lipid levels that occurs within a few hours of consuming fat is reduced by garlic or onion.
Two studies found that alliums inhibit platelet aggregation in human blood; another laboratory study found allicin, one of the components in garlic, had the same effect. Garlic also appears to
Amla, an ayurvedic herb, is used to treat hypercholesterolemia. In an uncontrolled study with a number of methodologic flaws, 50g of raw Amla ( Emblica officinalis), also called Indian gooseberry, was found to lower cholesterol in 35 men (some of whom were
Garlic may have an effect on mild hypertension, but studies have been mixed. In one double blind trial of 47 patients with mild
An analysis of eight trials with a total of 415 subjects found the general quality of trials poor; only three of the trials were limited to hypertensive patients. Four of the seven placebo-controlled trials found an effect on diastolic blood pressure.
Of 15 controlled trials on intermittent claudication, only two were deemed to be of acceptable quality. Both of these trials showed a
Chaste-tree berry ( Vitex agnus castus) may have profound hormonal effects. In a double blind placebo-controlled trial of 52 women with luteal phase defect due to latent hyperprolactinemia, one 20-mg capsule of Vitex daily reduced prolactin levels, normalized the
A double blind, placebo-controlled study of 36 newly diagnosed NIDDM patients compared two doses of standardized ginseng with
The herb St. John's wort ( Hypericum perforatum) is an effective treatment for mild to moderate depression. A meta-analysis of 23
St. John's wort also may cause photosensitivity. St. John's wort has mild MAO inhibition effects, but its antidepressant effects are
Ginkgo bilboa is very promising for the treatment of dementia. A placebo-controlled double blind study of a standardized ginkgo extract (EGb761) in 216 patients with Alzheimer's or multi-infarct dementia administered 240 mg of the extract daily for 24 weeks
Another placebo-controlled trial of 40 Alzheimer's patients given 80 mg of ginkgo extract three times daily found that patients given ginkgo improved in tests on memory, attention, psychopathologic disorder, and functional dynamics over those given placebo.
A third trial of 31 patients with mild to moderate memory impairment found a benefit of a standardized extract on cognitive
About 40 studies have been done on the use of ginkgo for the ill-defined diagnosis of cerebral insufficiency; a meta-analysis found that in seven of the eight best placebo-controlled trials, ginkgo was more
Ginkgo may help sexual dysfunction. An open trial of ginkgo was conducted in 37 male and female patients with serotonin reuptake inhibitor associated sexual problems, including erectile difficulty, delayed ejaculation, anorgasmia, and decreased libido. All patients had previously attempted to address sexual difficulties through the use of cyproheptadine, yohimbine, amantadine, buspirone, or dosage adjustment. After 4 weeks of taking 60 mg of ginkgo biloba extract three or four times a day, 86% reported significant improvement.
A double blind study of saw palmetto ( Serenoa repens) extract in 110 patients in France found that flow rate improved by 50%, and the number of nighttime bathroom trips also decreased significantly.
In an uncontrolled trial of saw palmetto in 305 men with mild to moderate symptoms of BPH, improvements in International Prostate Symptom Scores, quality of life scores, urinary flow rates, and residual urinary volume were seen after 45 days of
Echinacea (Echinacea augustifolia or E. purpurea) appears to enhance both cellular and humoral immunity. It is popular in Europe, especially in Germany, where more than 300 preparations of Echinacea are available.
A review of 26 controlled clinical trials (18 randomized, 11 double blind) of pure or mixed Echinacea preparations found positive results claimed for 30 of the 34 treated groups. Nineteen trials studied whether the preparation prevented or cured infections (most commonly upper respiratory infections), four trials the reduction of side effects of cancer therapies, and three looked at the effect of Echinacea on immune measures.
Authors of the review, however, note that although the evidence points to a positive effect of Echinacea on the immune system,
An herbal mixture was effective in the treatment of acute bronchiolitis in children with respiratory syncytial virus. In a single-blind
Ginger ( Zingiber officinale) may be a useful therapy for nausea and emesis of assorted causes. In a double blind crossover trial of 30
Ginger also is helpful in postoperative nausea and vomiting. In a double blind study that compared ginger, placebo, and
Evening primrose oil, a good source of gamma linolenic acid, has been evaluated in a double blind controlled trial of 56 women and found to be no more effective than placebo for hot flashes.
A 12-week, placebo-controlled trial of a Chinese herb mixture in 30 symptomatic HIV infection found no significant differences between the two groups in terms of symptoms, perceived health, or life satisfaction.
In one trial, a preparation containing Valerian officinalis with other ingredients was compared with an extract containing only
In a study of 27 patients with insomnia, patients received two pills and took one pill on the first night and the other on the second night. Both pills contained hops ( Flores humuli) and, apparently, lemon balm (Melissa officinalis, misnamed in the text), but one
Most plant-related poisonings are due to accidental consumption of toxic ornamental plants, not herbs. Mistaking poisonous plants for beneficial herbs has resulted in deaths (poison hemlock, for instance, has a superficial resemblance to parsley), but even correctly